[Fe (tFe) nm/Cu (tCu) nm]N multilayer films were prepared using pulsed-current electrodeposition method. The role of the pulsed-current deposition and Fe and Cu layer thicknesses on the magnetic properties was investigated. The microstructure of the multilayer films is dependent on the thicknesses of both the Fe and Cu layers. The saturation magnetization of the multilayers strongly correlated with the crystalline structure of Fe at the interface of Fe and Cu layers.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2488

Karki, B.R.

Rizal, C.

Ueda, Yu.

English

Ueda, Y.

Electronic Sumy State University Institutional Repository

JOURNAL OF NANO- AND ELECTRONIC PHYSICS ЖУРНАЛ НАНО-ТА ЕЛЕКТРОННОЇ ФІЗИКИ Vol. 4 No 1, 01001(3pp) (2012) Том 4 № 1, 01001(3cc) (2012)   2077-6772/2012/4(1)01001(3) 01001-1  2012 Sumy State University Magnetic Properties of Fe/Cu Multilayers Prepared Using Pulsed-Current Electrodeposition  C. Rizal1,*, Y. Ueda2, B.R. Karki3  1 University of British Columbia 2010-2332 Main Mall, V6T 1Z4, Vancouver, Canada 2 Muroran Institute of Technology 27-1 Mizomoto-Cho, 050-8585, Muroran, Japan 3 Texas Tech University 2500 Broadway, Texas Tech University, 79409, Lubbock, USA  (Received 18 June 2011; revised manuscript received 19 February 2012; published online 14 March 2012)  [Fe (tFe) nm/Cu (tCu) nm]N multilayer films were prepared using pulsed-current electrodeposition meth-od. The role of the pulsed-current deposition and Fe and Cu layer thicknesses on the magnetic properties was investigated. The microstructure of the multilayer films is dependent on the thicknesses of both the Fe and Cu layers. The saturation magnetization of the multilayers strongly correlated with the crystalline structure of Fe at the interface of Fe and Cu layers.  Keywords: Pulsed-current deposition, Fe/Cu, Multilayers, Saturation magnetization, Microstructure.   PACS numbers: 75.47.+a, 68.65.Ac   ______________ *crizal@ece.ubc.ca 1. INTRODUCTION  Interest in artificially tailored nanostructures has greatly surged in recent times because of their novel magnetic properties and potential technological appli-cations [1]. One of the excellent examples of artificially tailored nanostructure is Fe/Cu, which is composed of mutually insoluble metals such as iron and copper.  In spite of its complex structure, Fe can be combined with Cu to prepare multilayers of fcc-Cu and bcc-Fe [2]-[4].  Extensive studies have been done on the crystalline structure and magnetization properties of the multi-layers of Fe/Cu prepared by physical methods such as sputtering [5], [6], molecular beam epitaxy [7], and e-beam evaporation [8]. However, these methods require an ultra-high vacuum to control their film thicknesses. In contrast, the electrochemical method employs the liquid phase, which is relatively simple, inexpensive, and efficient for growing multilayers at the atomic level.  Pulse electrodeposition offers an easy adjustment of the current and time required in finding appropriate electrodeposition conditions.  It also offers direct con-trol over the composition and thickness, which can be achieved by adjusting the quantity of the pulsed-current through the electrolyte. Also, the thickness and composition of the multilayer containing the layers of Fe and Cu can be conveniently controlled by changing pulse amplitude and width [9]. Earlier, we reported findings on the chemical com-positions and magnetoresistance of compositionally modulated Fe-Cu-Ni alloys [9], and Fe-Ni [10] and Fe-Cu [11] multilayers and alloys.   In this study, we re-examine the relationship be-tween saturation magnetization and the microstruc-ture of the Fe/Cu multilayers. The saturation magneti-zation of the multilayer strongly correlated with the crystalline structure of Fe at the interface of Fe and Cu layers.  1. EXPERIMENTAL PROCEDURES  Fe/Cu multilayers were electrodeposited in a 250 cc glass beaker from a single sulphate electrolyte using pulsed-current deposition, which utilized two elec-trodes. The pulsed-current (potential) was supplied and controlled by a programmable micro-computer and a digital current source as shown in [12]. The solution was composed of FeSO4.6H2O (25.01 gm/litre), CuSo4.5H2O (2.5 gm/litre), and NaCl (2.5 gm/litre). Ammonium hydroxide (NH4OH) was used as a complexing agent because it improves the quality of the deposit [13]. The pH was maintained at 3.5 and it was controlled by the addition of sulphuric acid (H2SO4). The total composition of the solution was 0.1 mol/litre. The solution was prepared in double distilled water at room temperature. Further details are availa-ble in [11] and [14]. The distance between the cathode and anode was maintained at 2 cm. The current densi-ty was changed from 0.2 to 20 mA/cm2. Metal ions were collected at the cathode. Ferromagnetic Fe and non-magnetic Cu were alternately deposited to form very fine layered films. After deposition, the films were cleaned with double distilled water, dried, and immedi-ately wrapped in paraffin paper. The saturation magnetization of the Fe/Cu multi-layers was measured in the range of ± 21 kOe, using a vibrating sample magnetometer.  The microstructure was analyzed with CuKα radiation using an X-Ray dif-fractometer. The lattice spacing, d, was calculated from the diffraction curve using Bragg’s law as:   2dsin B  n  (1)  Where n is an integer,  is the wavelength of the X-rays, and B is the Bragg’s angle. The multilayer periodicity was determined using a composition of Fe and Cu in the film, and the composi-tion was estimated using micro-balance and energy dispersive X-ray analysis.  2. RESULTS AND DISCUSSIONS  Fig. 1 shows (a) pulsed-current waves with different widths and intervals and (b) the corresponding multi-layer structures.  The composition of each layer of Fe and Cu in (b) corresponds to the height of the pulse wave whereas the thickness corresponds to the pulse width, which is also a deposition time in (a). The beau- C. RIZAL, Y. UEDA, B.R. KARKI J. NANO- ELECTRON. PHYS.4, 01001 (2012)   01001-2 ty of this process is that by controlling both the pulse amplitude and widths one can produce various combi-nations of multilayers and alloys on an atomic scale via a single electrolyte [12].    Fig. 1 – Deposition times versus potential corresponding to the pulsed-current and (b) Film structures corresponding to (a)  Fig. 2 shows the saturation magnetization of [Fe 1 nm/Cu (tCu)]120 and [Fe 3 nm/Cu (tCu)]40 multilayers as the Cu layer thickness, tCu is changed from 0.5 to 2 nm. The total Ms tended to decrease when tCu is increased. However, decrease in magnetization for tFe  1 nm is different from when tFe  3 nm, and the gap between the two widens with the increase of tCu, i.e., the de-crease of Ms with tFe  1 nm is sharper than when tFe  3 nm. Furthermore, Ms tends to decrease when subject to heat treatment.  The reasons for the decrease in magnetization with the change in thickness of Cu layer are likely due to a change-over of fcc-Fe from the bcc-Fe crystalline struc-tures [14]. The reasons for further decrease in magneti-zation due to heat treatment are likely due to the inter-diffusions of Fe and Cu atoms at the interface [15] [16]. The details about how the lattice constant changes with the layer thickness are given in Figs. 3 and 4.  It should be noted that total Fe content in the multilayers was always kept constant. Fig. 3 shows the dependence of Cu layer thickness on the lattice constant of Fe, aFe, which increases as the Cu layer thickness, tCu, of [Fe 1 nm/Cu (tCu)]120 multi-layer is changed from 1 to 3 nm. The inset shows the X-ray diffraction curves. A sharp diffraction peak of [Fe 1 nm /Cu (tCu)]120 corre-sponding to bcc-Fe (110) is indicated by long dashed lines. When the fcc-Cu 111  layer thickness is in-creased, the peak shifts towards the lower side, and also results in a decrease in the diffraction peak height and an increase in the diffraction width, a sign of sig-nificant change in the crystalline structure of bcc-Fe (110) [15]. The broad peak of Fe (110) is believed to be originated from the intermixing of atoms of Fe and Cu in the interface as the thickness of Cu is increased [14].   Fig. 2 – Cu layer thickness, tCu dependence of the saturation magnetization of the [Fe1 nm/Cu (tCu) nm]120and [Fe3 nm/Cu (tCu) nm]40 multilayers: open rectangles (□): as-deposited and tFe  3 nm. Closed rectangles (■): annealed for 60 minutes at 300 C and tFe  3 nm. Open circles ( ): as-deposited and tFe  1 nm. Closed circles (●): annealed for 60 minutes at 300 C and tFe  1 nm    Fig. 3 – The lattice constant of Fe as the Cu layer is changed from 1 to 3 nm, obtained from the X-ray diffraction analysis.  The inset shows the X-ray diffraction pattern of [Fe 1 nm/Cu (tCu)]120 multilayer films  Fig. 4 shows the Fe layer thickness dependence on lat-tice spacing. The lattice spacing of [Fe (tFe) nm/Cu 1 nm]N multilayers, where N is varied from 120 to 40,  increas-es as the thickness of the Fe layer in the multilayer is     Fig. 4 – The lattice spacing, d110 of Fe/Cu multilayers as the Fe layer thickness, tFe is increased in thickness from 1 to 3 nm. The bulk values of d110 Fe, d111 Cu and d110 Fe + d111 Cu are indicated by straight dashed lines  MAGNETIC PROPERTIES OF FE/CU MULTILAYERS PREPARED… J. NANO- ELECTRON. PHYS.4, 01001 (2012)   01001-3 increased from 1 to 3 nm. The lattice spacing is lower than the bulk value of d110Fe for tFe < 1 nm, followed by an increase that approaches the bulk value of d110 Fe + d111 Cu for tFe  3 nm. These multilayers dis-play a combination of properties whose atomic struc-tures and properties vary strongly with the individual layer thickness of Fe and Cu, indicating how the elec-tronic structure might be engineered to enhance satu-ration magnetization [17].  3. CONCLUSIONS  We have observed unusual changes in the atomic structures of the Fe/Cu multilayers depending on the layer thickness of Fe and Cu. The change in the elec-tronic properties of Fe is believed to arise from the in-termixing of atoms at the interface between Fe and Cu layers. The thickness dependence of the magnetization-shows that the decrease in magnetization is caused by changes in the crystalline structures from bcc-Fe to fcc-Fe, which is consistent with the results of X-ray diffrac-tion. Research on the Fe/Cu multilayer is growing rapid-ly and has many technological applications including in the biomedical sectors.     REFERENCES 1. P.J. Sadashivaiah, T. Sankarappa, T. Sujatha, Santosh-kumar, R. Rawat, P. Sarvanan, A.K. Bhatnagar, Vacuum 85, 466 (2010). 2. C.L. Foiles, Ultramicroscopy 29, 80 (1989).  3. S.El. Khiraoui, M. Sajieddine, M. Hehn, S. Robert, C. Bellouard, M. Sahlaoui, K. Benkirane, Physica B 403 2509 (2008). 4. X. Jin, Y. Zhou, C.O. Kim, Y.P. Lee, H. Xu, S.K. Gong,  J. Appl. Phys. 91, 6071 (2002). 5. A.P. Kuprin, L. Cheng, D.W. Lee, Z. Altounian, D.H. Ryan, J. Appl. Phys. 85, 5738 (1999).  6. J.M. Florczak, E.D. Dahlberg, E.E. Fullerton, I.K. Schuller, J. Appl. Phys. 70, 5836 (1991). 7. Y. Harada, Y. Nakanishi, N. Yoshimoto, A. Yamaguchi, M. Nakamura, M. Yoshizawa, J. Magn. Magn. Mater. 272, e969 (2004). 8. J.F.M. Borges, G. Tosin, L.F. Schelp, N. Mattoso, S.R. Teixeira, D.H. Mosca, W.H. Schreiner, J. Magn. Magn. Mater. 121, 53 (1993).     9. C. Rizal, Y. Ueda, in International Conference on Magnetic Films and Surfaces (ICMFS), Kyoto, Japan, 27 (2001).  10. A. Yamada, M. Shirota, T. Houga, C. Rizal, Y. Ueda,  J. Japan Inst. of Metals 66, 869 (2002). 11. H. Zaman, A. Yamada, H. Fukuda, Y. Ueda, J. Electrochem. Soc. 145, 565 (1998). 12. A. Yamada, T. Houga, Y. Ueda, J. Magn. Magn. Mater. 239, 272 (2002).  13. I.W. Wolf, J. Appl. Phys. 33, 1152 (1962). 14. Y. Ueda, S. Ikeda, Y. Mori, H. Zaman, Mater. Sci. Eng. A 217, 371 (1996). 15. Y. Ueda, M. Takahashi, J. Magn. Magn. Mater. 71, 212 (1988).  16. R.M. Bozorth, Ferromagnetism (New York: Van Nostrand: 1947). 17. P. Ohresser, J. Shen, J. Barthel, M. Zheng, C.V. Mohan, M. Claua, J. Kirschner, Phys. Rev. B 55, 3696 (1999).   

Magnetic Properties of Fe/Cu Multilayers Prepared Using Pulsed-Current Electrodeposition

SocioEconomic Challenges Journal (Sumy State University)

JOURNAL OF NANO- AND ELECTRONIC PHYSICS ЖУРНАЛ НАНО-ТА ЕЛЕКТРОННОЇ ФІЗИКИ 
Vol. 4 No 1, 01001(3pp) (2012) Том 4 № 1, 01001(3cc) (2012) 
 
 
2077-6772/2012/4(1)01001(3) 01001-1  2012 Sumy State University 
Magnetic Properties of Fe/Cu Multilayers Prepared Using Pulsed-Current Electrodeposition 
 
C. Rizal1,*, Y. Ueda2, B.R. Karki3 
 
1 University of British Columbia 2010-2332 Main Mall, V6T 1Z4, Vancouver, Canada 
2 Muroran Institute of Technology 27-1 Mizomoto-Cho, 050-8585, Muroran, Japan 
3 Texas Tech University 2500 Broadway, Texas Tech University, 79409, Lubbock, USA 
 
(Received 18 June 2011; revised manuscript received 19 February 2012; published online 14 March 2012) 
 
[Fe (tFe) nm/Cu (tCu) nm]N multilayer films were prepared using pulsed-current electrodeposition meth-
od. The role of the pulsed-current deposition and Fe and Cu layer thicknesses on the magnetic properties 
was investigated. The microstructure of the multilayer films is dependent on the thicknesses of both the Fe 
and Cu layers. The saturation magnetization of the multilayers strongly correlated with the crystalline 
structure of Fe at the interface of Fe and Cu layers. 
 
Keywords: Pulsed-current deposition, Fe/Cu, Multilayers, Saturation magnetization, Microstructure. 
 
 PACS numbers: 75.47.+a, 68.65.Ac 
 
 
______________ 
*crizal@ece.ubc.ca 
1. INTRODUCTION 
 
Interest in artificially tailored nanostructures has 
greatly surged in recent times because of their novel 
magnetic properties and potential technological appli-
cations [1]. One of the excellent examples of artificially 
tailored nanostructure is Fe/Cu, which is composed of 
mutually insoluble metals such as iron and copper.  In 
spite of its complex structure, Fe can be combined with 
Cu to prepare multilayers of fcc-Cu and bcc-Fe [2]-[4].  
Extensive studies have been done on the crystalline 
structure and magnetization properties of the multi-
layers of Fe/Cu prepared by physical methods such as 
sputtering [5], [6], molecular beam epitaxy [7], and e-
beam evaporation [8]. However, these methods require 
an ultra-high vacuum to control their film thicknesses. 
In contrast, the electrochemical method employs the 
liquid phase, which is relatively simple, inexpensive, and 
efficient for growing multilayers at the atomic level.  
Pulse electrodeposition offers an easy adjustment of 
the current and time required in finding appropriate 
electrodeposition conditions.  It also offers direct con-
trol over the composition and thickness, which can be 
achieved by adjusting the quantity of the pulsed-
current through the electrolyte. Also, the thickness and 
composition of the multilayer containing the layers of 
Fe and Cu can be conveniently controlled by changing 
pulse amplitude and width [9]. 
Earlier, we reported findings on the chemical com-
positions and magnetoresistance of compositionally 
modulated Fe-Cu-Ni alloys [9], and Fe-Ni [10] and Fe-
Cu [11] multilayers and alloys.   
In this study, we re-examine the relationship be-
tween saturation magnetization and the microstruc-
ture of the Fe/Cu multilayers. The saturation magneti-
zation of the multilayer strongly correlated with the 
crystalline structure of Fe at the interface of Fe and Cu 
layers. 
 
1. EXPERIMENTAL PROCEDURES 
 
Fe/Cu multilayers were electrodeposited in a 250 cc 
glass beaker from a single sulphate electrolyte using 
pulsed-current deposition, which utilized two elec-
trodes. The pulsed-current (potential) was supplied and 
controlled by a programmable micro-computer and a 
digital current source as shown in [12]. 
The solution was composed of FeSO4.6H2O (25.01 
gm/litre), CuSo4.5H2O (2.5 gm/litre), and NaCl (2.5 
gm/litre). Ammonium hydroxide (NH4OH) was used as 
a complexing agent because it improves the quality of 
the deposit [13]. The pH was maintained at 3.5 and it 
was controlled by the addition of sulphuric acid 
(H2SO4). The total composition of the solution was 0.1 
mol/litre. The solution was prepared in double distilled 
water at room temperature. Further details are availa-
ble in [11] and [14]. The distance between the cathode 
and anode was maintained at 2 cm. The current densi-
ty was changed from 0.2 to 20 mA/cm2. Metal ions were 
collected at the cathode. Ferromagnetic Fe and non-
magnetic Cu were alternately deposited to form very 
fine layered films. After deposition, the films were 
cleaned with double distilled water, dried, and immedi-
ately wrapped in paraffin paper. 
The saturation magnetization of the Fe/Cu multi-
layers was measured in the range of ± 21 kOe, using a 
vibrating sample magnetometer.  The microstructure 
was analyzed with CuKα radiation using an X-Ray dif-
fractometer. The lattice spacing, d, was calculated from 
the diffraction curve using Bragg’s law as: 
 
 2dsin B  n  (1) 
 
Where n is an integer,  is the wavelength of the X-
rays, and B is the Bragg’s angle. 
The multilayer periodicity was determined using a 
composition of Fe and Cu in the film, and the composi-
tion was estimated using micro-balance and energy 
dispersive X-ray analysis. 
 
2. RESULTS AND DISCUSSIONS 
 
Fig. 1 shows (a) pulsed-current waves with different 
widths and intervals and (b) the corresponding multi-
layer structures.  The composition of each layer of Fe 
and Cu in (b) corresponds to the height of the pulse 
wave whereas the thickness corresponds to the pulse 
width, which is also a deposition time in (a). The beau-
 C. RIZAL, Y. UEDA, B.R. KARKI J. NANO- ELECTRON. PHYS.4, 01001 (2012) 
 
 
01001-2 
ty of this process is that by controlling both the pulse 
amplitude and widths one can produce various combi-
nations of multilayers and alloys on an atomic scale via 
a single electrolyte [12]. 
 
 
 
Fig. 1 – Deposition times versus potential corresponding to the 
pulsed-current and (b) Film structures corresponding to (a) 
 
Fig. 2 shows the saturation magnetization of [Fe 1 
nm/Cu (tCu)]120 and [Fe 3 nm/Cu (tCu)]40 multilayers as 
the Cu layer thickness, tCu is changed from 0.5 to 2 nm. 
The total Ms tended to decrease when tCu is increased. 
However, decrease in magnetization for tFe  1 nm is 
different from when tFe  3 nm, and the gap between 
the two widens with the increase of tCu, i.e., the de-
crease of Ms with tFe  1 nm is sharper than when 
tFe  3 nm. Furthermore, Ms tends to decrease when 
subject to heat treatment.  
The reasons for the decrease in magnetization with 
the change in thickness of Cu layer are likely due to a 
change-over of fcc-Fe from the bcc-Fe crystalline struc-
tures [14]. The reasons for further decrease in magneti-
zation due to heat treatment are likely due to the inter-
diffusions of Fe and Cu atoms at the interface [15] [16]. 
The details about how the lattice constant changes 
with the layer thickness are given in Figs. 3 and 4.  It 
should be noted that total Fe content in the multilayers 
was always kept constant. 
Fig. 3 shows the dependence of Cu layer thickness 
on the lattice constant of Fe, aFe, which increases as the 
Cu layer thickness, tCu, of [Fe 1 nm/Cu (tCu)]120 multi-
layer is changed from 1 to 3 nm. 
The inset shows the X-ray diffraction curves. A 
sharp diffraction peak of [Fe 1 nm /Cu (tCu)]120 corre-
sponding to bcc-Fe (110) is indicated by long dashed 
lines. When the fcc-Cu 111  layer thickness is in-
creased, the peak shifts towards the lower side, and 
also results in a decrease in the diffraction peak height 
and an increase in the diffraction width, a sign of sig-
nificant change in the crystalline structure of bcc-Fe 
(110) [15]. The broad peak of Fe (110) is believed to be 
originated from the intermixing of atoms of Fe and Cu 
in the interface as the thickness of Cu is increased [14]. 
 
 
Fig. 2 – Cu layer thickness, tCu dependence of the saturation 
magnetization of the [Fe1 nm/Cu (tCu) nm]120and [Fe3 nm/Cu (tCu) 
nm]40 multilayers: open rectangles (□): as-deposited and tFe  3 
nm. Closed rectangles (■): annealed for 60 minutes at 300 C and 
tFe  3 nm. Open circles ( ): as-deposited and tFe  1 nm. Closed 
circles (●): annealed for 60 minutes at 300 C and tFe  1 nm 
 
 
 
Fig. 3 – The lattice constant of Fe as the Cu layer is changed 
from 1 to 3 nm, obtained from the X-ray diffraction analysis.  
The inset shows the X-ray diffraction pattern of [Fe 1 nm/Cu 
(tCu)]120 multilayer films 
 
Fig. 4 shows the Fe layer thickness dependence on lat-
tice spacing. The lattice spacing of [Fe (tFe) nm/Cu 1 nm]N 
multilayers, where N is varied from 120 to 40,  increas-
es as the thickness of the Fe layer in the multilayer is  
 
 
 
Fig. 4 – The lattice spacing, d110 of Fe/Cu multilayers as the 
Fe layer thickness, tFe is increased in thickness from 1 to 3 
nm. The bulk values of d110 Fe, d111 Cu and d110 Fe + d111 Cu are 
indicated by straight dashed lines 
 MAGNETIC PROPERTIES OF FE/CU MULTILAYERS PREPARED… J. NANO- ELECTRON. PHYS.4, 01001 (2012) 
 
 
01001-3 
increased from 1 to 3 nm. The lattice spacing is lower 
than the bulk value of d110Fe for tFe < 1 nm, followed 
by an increase that approaches the bulk value of 
d110 Fe + d111 Cu for tFe  3 nm. These multilayers dis-
play a combination of properties whose atomic struc-
tures and properties vary strongly with the individual 
layer thickness of Fe and Cu, indicating how the elec-
tronic structure might be engineered to enhance satu-
ration magnetization [17]. 
 
3. CONCLUSIONS 
 
We have observed unusual changes in the atomic 
structures of the Fe/Cu multilayers depending on the 
layer thickness of Fe and Cu. The change in the elec-
tronic properties of Fe is believed to arise from the in-
termixing of atoms at the interface between Fe and Cu 
layers. The thickness dependence of the magnetization-
shows that the decrease in magnetization is caused by 
changes in the crystalline structures from bcc-Fe to fcc-
Fe, which is consistent with the results of X-ray diffrac-
tion. Research on the Fe/Cu multilayer is growing rapid-
ly and has many technological applications including in 
the biomedical sectors. 
 
 
 
 
REFERENCES 
1. P.J. Sadashivaiah, T. Sankarappa, T. Sujatha, Santosh-
kumar, R. Rawat, P. Sarvanan, A.K. Bhatnagar, Vacuum 
85, 466 (2010). 
2. C.L. Foiles, Ultramicroscopy 29, 80 (1989).  
3. S.El. Khiraoui, M. Sajieddine, M. Hehn, S. Robert, 
C. Bellouard, M. Sahlaoui, K. Benkirane, Physica B 403 
2509 (2008). 
4. X. Jin, Y. Zhou, C.O. Kim, Y.P. Lee, H. Xu, S.K. Gong,  
J. Appl. Phys. 91, 6071 (2002). 
5. A.P. Kuprin, L. Cheng, D.W. Lee, Z. Altounian, D.H. Ryan, 
J. Appl. Phys. 85, 5738 (1999).  
6. J.M. Florczak, E.D. Dahlberg, E.E. Fullerton, I.K. Schuller, 
J. Appl. Phys. 70, 5836 (1991). 
7. Y. Harada, Y. Nakanishi, N. Yoshimoto, A. Yamaguchi, 
M. Nakamura, M. Yoshizawa, J. Magn. Magn. Mater. 272, 
e969 (2004). 
8. J.F.M. Borges, G. Tosin, L.F. Schelp, N. Mattoso, S.R. Teixeira, 
D.H. Mosca, W.H. Schreiner, J. Magn. Magn. Mater. 121, 
53 (1993).  
 
 
 
9. C. Rizal, Y. Ueda, in International Conference on Magnetic 
Films and Surfaces (ICMFS), Kyoto, Japan, 27 (2001).  
10. A. Yamada, M. Shirota, T. Houga, C. Rizal, Y. Ueda,  
J. Japan Inst. of Metals 66, 869 (2002). 
11. H. Zaman, A. Yamada, H. Fukuda, Y. Ueda, J. Electrochem. 
Soc. 145, 565 (1998). 
12. A. Yamada, T. Houga, Y. Ueda, J. Magn. Magn. Mater. 
239, 272 (2002).  
13. I.W. Wolf, J. Appl. Phys. 33, 1152 (1962). 
14. Y. Ueda, S. Ikeda, Y. Mori, H. Zaman, Mater. Sci. Eng. A 
217, 371 (1996). 
15. Y. Ueda, M. Takahashi, J. Magn. Magn. Mater. 71, 212 
(1988).  
16. R.M. Bozorth, Ferromagnetism (New York: Van Nostrand: 
1947). 
17. P. Ohresser, J. Shen, J. Barthel, M. Zheng, C.V. Mohan, 
M. Claua, J. Kirschner, Phys. Rev. B 55, 3696 (1999). 
 
 


198                   Nanomaterials: Applications and Properties (NAP-2011). Vol. 2, Part I            
 
MAGNETIC PROPERTIES OF Fe/Cu MULTILAYERS 
PREPARED USING PULSED-CURRENT  
ELECTRODEPOSITION 
Conrad Rizal1*, Yuji Ueda2, and Bhishma R. Karki3 
 
1 Department of Electrical and Computer Engineering, University of British Columbia, Vancou-
ver, BC, V6T 1Z4, Canada 
2 Department of Electrical and Electronic Engineering, Muroran Institute of Technology, Hokkai-
do, 050-8585, Japan 
3 Department of Physics, Texas Tech University, Lubbock, TX, 79409, USA 
 
ABSTRACT 
[Fe (tFe) nm/Cu (tCu) nm]N multilayer films were prepared using pulsed-current elec-
trodeposition method.  The role of the pulsed-current electrodeposition on microstruc-
ture and magnetic properties was investigated.  The microstructure of the multilayer 
films is dependent on the thicknesses of both the Fe and Cu layers.  The saturation mag-
netization of the multilayers strongly correlated with the crystalline structure of Fe at the 
interface of Fe and Cu layers. 
 
Key words: pulsed-current electrodeposition, Fe/Cu, multilayers, saturation magnet-
ization, microstructure 
 
INTRODUCTION 
Interest in artificially tailored nanostructures has greatly surged in recent 
times because of their novel magnetic properties and potential technological 
applications [1].  One of the excellent examples of artificially tailored 
nanostructure is Fe/Cu, which is composed of mutually insoluble metals such 
as iron and copper.  In spite of its complex structure, Fe can be combined with 
Cu to prepare multilayers of fcc-Cu and bcc-Fe [2-4].  Extensive studies have 
been done on the crystalline structure and magnetization properties of the mul-
tilayers of Fe/Cu prepared by physical methods such as sputtering [5, 6], mo-
lecular beam epitaxy [7], and e-beam evaporation [8].  However, these methods 
require an ultra-high vacuum to control their film thicknesses. In contrast,  the 
electrochemical method employs the liquid phase, which is relatively simple, 
inexpensive, and efficient for growing multilayers at the atomic level.  
Pulse electrodeposition offers an easy adjustment of the current and time 
required in finding appropriate electrodeposition conditions.  It also offers di-
rect control over the composition and thickness, which can be achieved by 
adjusting the quantity of the pulsed-current through the electrolyte.  Also, the 
                                               
* e-mail: crizal@ece.ubc.ca, tel:+1(604)8226268, fax:+1(604)8225949 
Nanomaterials: Applications and Properties (NAP-2011). Vol. 2, Part I                   199 
 
thickness and composition of the multilayer containing the layers of Fe and Cu 
can be conveniently controlled by changing pulse amplitude and width [9]. 
Earlier, we reported findings on the chemical compositions and magneto-
resistance of compositionally modulated Fe-Cu-Ni alloys [9], and Fe-Ni [10] 
and Fe-Cu [11] multilayers and alloys.   
In this study, we re-examine the relationship between saturation magneti-
zation and the microstructure of the Fe/Cu multilayers.  The saturation magnet-
ization of the multilayer strongly correlated with the crystalline structure of Fe 
at the interface of Fe and Cu layers. 
EXPERIMENTAL PROCEDURES 
Fe/Cu multilayers were electrodeposited in a 250 cc glass beaker from a 
single sulphate electrolyte using pulsed-current electrodeposition, which uti-
lized two electrodes. The pulsed-current (potential) was supplied and controlled 
by a programmable micro-computer and a digital current source as shown in 
[12].   
The solution was composed of FeSO4.6H2O (25.01 gm/litre), CuSo4.5H20 
(2.5 gm/litre), and NaCl (2.5 gm/litre).  Ammonium hydroxide (NH4OH) was 
used as a complexing agent because it improves the quality of the deposit [13].  
The pH was maintained at 3.5 and it was controlled by the addition of sulphuric 
acid (H2SO4).  The total composition of the solution was 0.1 mol/litre.  The 
solution was prepared in double distilled water.  The temperature of the bath 
was maintained at room temperature.  Further details are available in [11] and 
[14]. The distance between the cathode and anode was maintained at 2 cm.  The 
current density was changed from 0.2 to 20 mA/cm2.. Metal ions were collected 
at the cathode.  Ferromagnetic Fe and non-magnetic Cu were alternately depos-
ited to form very fine layered films.  After deposition, the films were cleaned 
with double distilled water, dried, and immediately wrapped in paraffin paper. 
The saturation magnetization of the Fe/Cu multilayers was measured in 
the range of ± 21 kOe, using a vibrating sample magnetometer.  The micro-
structure was analyzed with CuK? radiation using an X-Ray diffractometer.  
The lattice spacing, d, was calculated from the diffraction curve using Bragg’s 
law as: 
?? nd B ?sin2    (1) 
where n is the integer, ? is the wavelength of the X-rays, and ?B is  the  
Bragg’s angle. 
The multilayer periodicity was determined using a composition of Fe and 
Cu in the film, and the composition was estimated using micro-balance and 
energy dispersive X-ray analysis. 
RESULTS AND DISCUSSIONS 
Fig.1a shows  pulsed-current waves with different widths and intervals 
200                   Nanomaterials: Applications and Properties (NAP-2011). Vol. 2, Part I            
 
and (Fig 1b) the corresponding multilayer structures.  The composition of each 
layer  of  Fe  and  Cu  in  (Fig 1b) corresponds to the height of the pulse wave 
whereas the thickness corresponds to the pulse width, which is also a deposition 
time in (Fig 1a).  The beauty of this process is that by controlling both the pulse 
amplitude and widths one can produce various combinations of multilayers and 
alloys on an atomic scale via a single electrolyte [12]. 
Fig.2 shows the satura-
tion magnetization of [Fe 1 
nm/Cu (tCu)]120 and  [Fe  3  
nm/Cu (tCu)]40  multilayers as 
the Cu layer thickness, tCu is 
changed from 0.5 to 2 nm.  
The total Ms tended to de-
crease when tCu is increased.  
However, decrease in mag-
netization for tFe= 1 nm is 
different from when tFe= 3 
nm, and the gap between the 
two widens with the in-
crease of tCu, i.e., the de-
crease of Ms with tFe= 1 nm 
is sharper than when tFe= 3 
nm.  Furthermore, Ms tends 
to decrease when subject to 
heat treatment.  
The reasons for the decrease in magnetization with the change in thickness 
of Cu layer are likely due to a change-over of fcc-Fe from the bcc-Fe crystal-
line structures [14]. The reasons for further decrease in magnetization due to 
heat treatment are likely due to the inter-diffusions of Fe and Cu atoms at the 
interface [15] [16].   
 
Fig. 2 – Cu layer thickness, tCu 
dependence of the saturation 
magnetization of the [Fe1 
nm/Cu (tCu) nm]120 and [Fe3 
nm/Cu (tCu) nm]40 multilayers: 
Open rectangles (?): as-
deposited and tFe= 3 nm. Closed 
rectangles (?): Annealed for 60 
minutes at 300 0C and tFe= 3 
nm.  Open  circles  (?): as-
deposited and tFe= 1 nm. Closed 
circles (?): Annealed for 60 
minutes at 3000C and tFe= 1 nm. 
 
Fig.1 - (a) Deposition times versus potential  
corresponding to the pulsed-current and (b)  
Film structures corresponding to (a). 
Nanomaterials: Applications and Properties (NAP-2011). Vol. 2, Part I                   201 
 
The details about how the lattice constant changes with the layer thickness 
are given in Fig.  3 and Fig.4.  It should be noted that total Fe content in the 
multilayers is always kept constant. 
Fig. 3 shows the dependence of Cu layer thickness on the lattice constant 
of Fe, aFe, which increases as the Cu layer thickness,  tCu,  of  [Fe  1  nm  /Cu  
(tCu)]120 multilayer is changed from 1 to 3 nm.   
The inset shows the X-ray diffraction curves.  A sharp diffraction peak of 
[Fe 1 nm /Cu (tCu)]120 corresponding to bcc-Fe (110) is indicated by long dashed 
lines.  When the fcc-Cu<111> layer thickness is increased, the peak shifts to-
wards the lower side, and also results in a decrease in the diffraction peak 
height and an increase in the diffraction width, a sign of significant change in 
the crystalline structure of bcc-Fe (110) [15].  The broad peak of Fe (110) is 
believed  to  be  originated  from  the  intermixing  of  atoms  of  Fe  and  Cu  in  the  
interface as the thickness of Cu is increased [14]. 
 
  
Fig. 3 – The lattice constant of Fe as the 
Cu layer is changed from 1 to 3 nm, ob-
tained from the X-ray diffraction analysis.  
The inset shows the X-ray diffraction 
pattern of [Fe 1 nm /Cu (tCu)]120 multilayer 
films. 
Fig. 4 – The lattice spacing, d110 of Fe/Cu 
multilayers as the Fe layer thickness, tFe is 
increased in thickness from 1 to 3 nm.  
The bulk values of d110Fe, d111Cu and 
d110Fe+d111Cu are indicated by straight 
dashed lines. 
 
Fig.  4 shows the Fe layer thickness dependence on lattice spacing.  The 
lattice spacing of [Fe (tFe) nm/Cu 1 nm]N  multilayers, where N is varied from 
120  to  40,   increases  as  the  thickness  of  the  Fe  layer  in  the  multilayer  is  in-
creased  from  1  to  3  nm.   The  lattice  spacing  is  lower  than  the  bulk  value  of  
d110Fe for tFe<1 nm, followed by an increase that approaches the bulk value of 
d110Fe+d111Cu for tFe = 3 nm.  These multilayers display a combination of prop-
erties whose atomic structures and properties vary strongly with the individual 
layer thickness of Fe and Cu, indicating how the electronic structure might be 
engineered to enhance saturation magnetization [17]. 
202                   Nanomaterials: Applications and Properties (NAP-2011). Vol. 2, Part I            
 
CONCLUSIONS 
We have observed unusual changes in the atomic structures of the Fe/Cu 
multilayers depending on the layer thickness of Fe and Cu.  The change in the 
electronic properties of Fe is believed to arise from the intermixing of atoms at 
the interface between Fe and Cu layers.  The thickness dependence of the mag-
netization shows that the decrease in magnetization is caused by changes in the 
crystalline structures from bcc-Fe to fcc-Fe, which is consistent with the results 
of X-ray diffraction. Research on the Fe/Cu multilayer is growing rapidly and 
has many technological applications including in the biomedical sectors. 
 
Acknowledgements 
The authors are grateful to the Natural Science and Engineering Research 
Council scholarship, Government of Canada, for partial funding for this work. 
REFERENCES 
[1] P. J. Sadashivaiah, T. Sankarappa, T. Sujathaet al. Vacuum, 2010, vol. 85, pp. 466-
473  
[2] C. L. Foiles, Ultra-microscopy, 1989, vol. 29, pp. 80-87.  
[3] S. El Khiraoui, M. Sajieddine, M. Hehn, et al. Physica B: Condensed Matter, 2008, 
vol. 403, pp. 2509-2514.  
[4]  X. Jin, Y. Zhou, C. O. Kim, et al. J. Appl. Phys., 2002, vol. 91, pp. 6071-6076.  
[5]  A. P. Kuprin, L. Cheng, D. W. Lee, et al. J. Appl. Phys.,1999, vol. 85, pp. 5738-
5740.  
[6] J. M. Florczak, E. D. Dahlberg, E. E. Fullerton and I. K. Schuller,  J. Appl. Phys., 
1991, vol. 70, pp. 5836-5836.  
[7] Y. Harada, Y. Nakanishi, N. Yoshimoto et al. J. Magn. Magn. Mater., 2004, vol. 
272-276, pp. e969-e970.  
[8] J. F. M. Borges, G. Tosin, L. F. Schelp, et al. J. Magn. Magn. Mater., 1993, vol. 
121, pp. 53-56.  
[9] C. Rizal and Y. Ueda, International Conference on Magnetic Films and Surfaces 
(ICMFS), Kyoto, Japan, 2001, pp. 27-28.  
[10]  A.  Yamada,  M.  Shirota,  T.  Houga,  C.  Rizal,  Y.  Ueda,  Japan  Inst.  of  Metals,  
2002,vol. 66, pp. 869-872.  
[11] H. Zaman, A. Yamada, H. Fukuda, Y. Ueda, J. Electrochem, Soc., 1998,vol. 145, 
pp. 565-568.  
[12] A. Yamada, T. Houga and Y. Ueda, J. Magn. Magn. Mater., 2002, vol. 239, pp. 
272-275, 2.  
[13] I. W. Wolf,Appl. Phys., 1962, vol. 33, pp. 1152-1159.  
[14] Y. Ueda, S. Ikeda, Y. Mori, H. Zaman, Materials Science and Engineering (A), 
1996, vol. 217, pp. 371-375. 
[15] Y. Ueda and M. Takahashi, J Magn Magn Mater, 1988, vol. 71, pp. 212-218.  
[16] R. M. Bozorth, Ferromagnetism. New York: Van Nostrand, 1947., pp.48 
[17] P. Ohresser, J., Shen, J. Barthel, et al. Phys. Rev. B, 1999, vol. 55 (5), pp. 3696-
3706 
  


Magnetic properties of Fe/Cu multilayers prepared using pulsed-current electrodeposition

198                   Nanomaterials: Applications and Properties (NAP-2011). Vol. 2, Part I             MAGNETIC PROPERTIES OF Fe/Cu MULTILAYERS PREPARED USING PULSED-CURRENT  ELECTRODEPOSITION Conrad Rizal1*, Yuji Ueda2, and Bhishma R. Karki3  1 Department of Electrical and Computer Engineering, University of British Columbia, Vancou-ver, BC, V6T 1Z4, Canada 2  Department of Electrical and Electronic Engineering, Muroran Institute of Technology, Hokkai-do, 050-8585, Japan 3  Department of Physics, Texas Tech University, Lubbock, TX, 79409, USA  ABSTRACT [Fe (tFe) nm/Cu (tCu) nm]N multilayer films were prepared using pulsed-current elec-trodeposition method.  The role of the pulsed-current electrodeposition on microstruc-ture and magnetic properties was investigated.  The microstructure of the multilayer films is dependent on the thicknesses of both the Fe and Cu layers.  The saturation mag-netization of the multilayers strongly correlated with the crystalline structure of Fe at the interface of Fe and Cu layers.  Key words: pulsed-current electrodeposition, Fe/Cu, multilayers, saturation magnet-ization, microstructure  INTRODUCTION Interest in artificially tailored nanostructures has greatly surged in recent times because of their novel magnetic properties and potential technological applications [1].  One of the excellent examples of artificially tailored nanostructure is Fe/Cu, which is composed of mutually insoluble metals such as iron and copper.  In spite of its complex structure, Fe can be combined with Cu to prepare multilayers of fcc-Cu and bcc-Fe [2-4].  Extensive studies have been done on the crystalline structure and magnetization properties of the mul-tilayers of Fe/Cu prepared by physical methods such as sputtering [5, 6], mo-lecular beam epitaxy [7], and e-beam evaporation [8].  However, these methods require an ultra-high vacuum to control their film thicknesses. In contrast, the electrochemical method employs the liquid phase, which is relatively simple, inexpensive, and efficient for growing multilayers at the atomic level.  Pulse electrodeposition offers an easy adjustment of the current and time required in finding appropriate electrodeposition conditions.  It also offers di-rect control over the composition and thickness, which can be achieved by adjusting the quantity of the pulsed-current through the electrolyte.  Also, the                                                  * e-mail: crizal@ece.ubc.ca, tel:+1(604)8226268, fax:+1(604)8225949 Nanomaterials: Applications and Properties (NAP-2011). Vol. 2, Part I                   199  thickness and composition of the multilayer containing the layers of Fe and Cu can be conveniently controlled by changing pulse amplitude and width [9]. Earlier, we reported findings on the chemical compositions and magneto-resistance of compositionally modulated Fe-Cu-Ni alloys [9], and Fe-Ni [10] and Fe-Cu [11] multilayers and alloys.   In this study, we re-examine the relationship between saturation magneti-zation and the microstructure of the Fe/Cu multilayers.  The saturation magnet-ization of the multilayer strongly correlated with the crystalline structure of Fe at the interface of Fe and Cu layers. EXPERIMENTAL PROCEDURES Fe/Cu multilayers were electrodeposited in a 250 cc glass beaker from a single sulphate electrolyte using pulsed-current electrodeposition, which uti-lized two electrodes. The pulsed-current (potential) was supplied and controlled by a programmable micro-computer and a digital current source as shown in [12].   The solution was composed of FeSO4.6H2O (25.01 gm/litre), CuSo4.5H20 (2.5 gm/litre), and NaCl (2.5 gm/litre).  Ammonium hydroxide (NH4OH) was used as a complexing agent because it improves the quality of the deposit [13].  The pH was maintained at 3.5 and it was controlled by the addition of sulphuric acid (H2SO4).  The total composition of the solution was 0.1 mol/litre.  The solution was prepared in double distilled water.  The temperature of the bath was maintained at room temperature.  Further details are available in [11] and [14]. The distance between the cathode and anode was maintained at 2 cm.  The current density was changed from 0.2 to 20 mA/cm2.. Metal ions were collected at the cathode.  Ferromagnetic Fe and non-magnetic Cu were alternately depos-ited to form very fine layered films.  After deposition, the films were cleaned with double distilled water, dried, and immediately wrapped in paraffin paper. The saturation magnetization of the Fe/Cu multilayers was measured in the range of ± 21 kOe, using a vibrating sample magnetometer.  The micro-structure was analyzed with CuKĮ radiation using an X-Ray diffractometer.  The lattice spacing, d, was calculated from the diffraction curve using Bragg’s law as: O T n d B   sin 2      (1) where n is the integer, O is the wavelength of the X-rays, and TB is the Bragg’s angle. The multilayer periodicity was determined using a composition of Fe and Cu in the film, and the composition was estimated using micro-balance and energy dispersive X-ray analysis. RESULTS AND DISCUSSIONS Fig.1a shows  pulsed-current waves with different widths and intervals 200                   Nanomaterials: Applications and Properties (NAP-2011). Vol. 2, Part I             and (Fig 1b) the corresponding multilayer structures.  The composition of each lay er of Fe and Cu in (Fig 1b) corresponds to the height of the pulse wave whereas the thickness corresponds to the pulse width, which is also a deposition time in (Fig 1a).  The beauty of this process is that by controlling both the pulse amplitude and widths one can produce various combinations of multilayers and alloys on an atomic scale via a single electrolyte [12]. Fig.2 shows the satura-tion magnetization of [Fe 1 nm/Cu (tCu)]120 a n d  [ F e  3 nm/Cu (tCu)]40  multilayers as the Cu layer thickness, tCu is changed from 0.5 to 2 nm.  The total Ms  tended to de-crease when tCu is increased.  However, decrease in mag-netization for tFe= 1 nm is different from when tFe= 3 nm, and the gap between the two widens with the in-crease of tCu, i.e., the de-crease of Ms with tFe= 1 nm is sharper than when tFe= 3 nm.  Furthermore, Ms tends to decrease when subject to heat treatment.  The reasons for the decrease in magnetization with the change in thickness of Cu layer are likely due to a change-over of fcc-Fe from the bcc-Fe crystal-line structures [14]. The reasons for further decrease in magnetization due to heat treatment are likely due to the inter-diffusions of Fe and Cu atoms at the interface [15] [16].    Fig. 2 – Cu layer thickness, tCu dependence of the saturation magnetization  of  the [Fe1 nm/Cu (tCu) nm]120  and  [Fe3 nm/Cu (tCu) nm]40  multilayers: Open rectangles (Ƒ): as-deposited and tFe= 3 nm. Closed rectangles (Ŷ): Annealed for 60 minutes at 300 0C and tFe= 3 n m .  O p e n  c i r c l e s  ( R ): as-deposited and tFe= 1 nm. Closed circles (Ɣ): Annealed for 60 minutes at 3000C and tFe= 1 nm.  Fig.1 - (a) Deposition times versus potential  corresponding to the pulsed-current and (b)  Film structures corresponding to (a). Nanomaterials: Applications and Properties (NAP-2011). Vol. 2, Part I                   201  The details about how the lattice constant changes with the layer thickness are given in Fig. 3 and Fig.4.  It should be noted that total Fe content in the multilayers is always kept constant. Fig. 3 shows the dependence of Cu layer thickness on the lattice constant of Fe, aFe, which increases as the Cu layer thickness, t Cu, of [Fe 1 nm /C u (t Cu)]120 multilayer is changed from 1 to 3 nm.   The inset shows the X-ray diffraction curves.  A sharp diffraction peak of [Fe 1 nm /Cu (tCu)]120 corresponding to bcc-Fe (110) is indicated by long dashed lines.  When the fcc-Cu<111> layer thickness is increased, the peak shifts to-wards the lower side, and also results in a decrease in the diffraction peak height and an increase in the diffraction width, a sign of significant change in the crystalline structure of bcc-Fe (110) [15].  The broad peak of Fe (110) is believed to be originated from the intermixing of atoms of Fe and Cu in the interface as the thickness of Cu is increased [14].     Fig. 3 – The lattice constant of Fe as the Cu layer is changed from 1 to 3 nm, ob-tained from the X-ray diffraction analysis.  The inset shows the X-ray diffraction pattern of [Fe 1 nm /Cu (tCu)]120 multilayer films. Fig. 4 – The lattice spacing, d110 of Fe/Cu multilayers as the Fe layer thickness, tFe is increased in thickness from 1 to 3 nm.  The bulk values of d110Fe, d111Cu and d110Fe+d111Cu are indicated by straight dashed lines.  Fig. 4 shows the Fe layer thickness dependence on lattice spacing.  The lattice spacing of [Fe (tFe) nm/Cu 1 nm]N  multilayers, where N is varied from 120 to 40,  increases as the thickness of the Fe layer in the multilayer is in-creased from 1 to 3 nm.  The lattice spacing is lower than the bulk value of d 110Fe for tFe<1 nm, followed by an increase that approaches the bulk value of d110Fe+d111Cu for tFe = 3 nm.  These multilayers display a combination of prop-erties whose atomic structures and properties vary strongly with the individual layer thickness of Fe and Cu, indicating how the electronic structure might be engineered to enhance saturation magnetization [17]. 202                   Nanomaterials: Applications and Properties (NAP-2011). Vol. 2, Part I             CONCLUSIONS We have observed unusual changes in the atomic structures of the Fe/Cu multilayers depending on the layer thickness of Fe and Cu.  The change in the electronic properties of Fe is believed to arise from the intermixing of atoms at the interface between Fe and Cu layers.  The thickness dependence of the mag-netization shows that the decrease in magnetization is caused by changes in the crystalline structures from bcc-Fe to fcc-Fe, which is consistent with the results of X-ray diffraction. Research on the Fe/Cu multilayer is growing rapidly and has many technological applications including in the biomedical sectors.  Acknowledgements The authors are grateful to the Natural Science and Engineering Research Council scholarship, Government of Canada, for partial funding for this work. REFERENCES [1] P. J. Sadashivaiah, T. Sankarappa, T. Sujathaet al. Vacuum, 2010, vol. 85, pp. 466-473  [2] C. L. Foiles, Ultra-microscopy, 1989, vol. 29, pp. 80-87.  [3] S. El Khiraoui, M. Sajieddine, M. Hehn, et al. Physica B: Condensed Matter, 2008, vol. 403, pp. 2509-2514.  [4]  X. Jin, Y. Zhou, C. O. Kim, et al. J. Appl. Phys., 2002, vol. 91, pp. 6071-6076.  [5]   A. P. Kuprin, L. Cheng, D. W. Lee, et al. J. Appl. Phys.,1999, vol. 85, pp. 5738-5740.  [6] J. M. Florczak, E. D. Dahlberg, E. E. Fullerton and I. K. Schuller,  J. Appl. Phys., 1991, vol. 70, pp. 5836-5836.  [7] Y. Harada, Y. Nakanishi, N. Yoshimoto et al. J. Magn. Magn. Mater., 2004, vol. 272-276, pp. e969-e970.  [8] J. F. M. Borges, G. Tosin, L. F. Schelp, et al. J. Magn. Magn. Mater., 1993, vol. 121, pp. 53-56.  [9] C. Rizal and Y. Ueda, International Conference on Magnetic Films and Surfaces (ICMFS), Kyoto, Japan, 2001, pp. 27-28.  [ 10] A . Y am ada, M . S hi ro ta , T . H o ug a, C . R iz al , Y . U eda , J apan  I nst . o f  Metal s, 2002,vol. 66, pp. 869-872.  [11]  H. Zaman, A. Yamada, H. Fukuda, Y. Ueda, J. Electrochem, Soc., 1998,vol. 145, pp. 565-568.  [12]  A. Yamada, T. Houga and Y. Ueda, J. Magn. Magn. Mater., 2002, vol. 239, pp. 272-275, 2.  [13]  I. W. Wolf,Appl. Phys., 1962, vol. 33, pp. 1152-1159.  [14]  Y. Ueda, S. Ikeda, Y. Mori, H. Zaman, Materials Science and Engineering (A), 1996, vol. 217, pp. 371-375. [15] Y. Ueda and M. Takahashi, J Magn Magn Mater, 1988, vol. 71, pp. 212-218.  [16]  R. M. Bozorth, Ferromagnetism. New York: Van Nostrand, 1947., pp.48 [17]  P. Ohresser, J., Shen, J. Barthel, et al. Phys. Rev. B, 1999, vol. 55 (5), pp. 3696-3706    

S hi ro ta , T . H o ug a,

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Magnetic properties of Fe/Cu multilayers prepared using pulsed-current electrodeposition

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