The paper deals with the methods of forming three-layer structures by layer condensation of nanoscale
films Ni, Fe and V. Investigated the magnetoresistive properties of the samples as well as their dependence
on annealing temperature and the thickness of nonmagnetic layer. The correlation of magnetoresistance
effect with structural-phase state of film system and its components are defined.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3506

Bibyk, Vitalii Volodymyrovych

Grischuk, A.S.

Hrychanovska, Tetiana Mykhailivna

Sheshenya, L.A.

Бибик, Виталий Владимирович

Бібик, Віталій Володимирович

Гричановская, Татьяна Михайловна

Гричановська, Тетяна Михайлівна

SocioEconomic Challenges Journal (Sumy State University)

PROCEEDINGS OF THE INTERNATIONAL CONFERENCE NANOMATERIALS: APPLICATIONS AND PROPERTIES 
Vol. 1 No 3, 03TF18(3pp) (2012) 
 
 
2304-1862/2012/1(3)03TF18(3) 03TF18-1  2012 Sumy State University 
Magnetoresistive Properties of Three-Layer Systems on the Basis of Thin Metal Films  
Fe and V or Ni and V 
 
V.V. Bibik, T.M. Grichanovskaya, A.S. Grischuk, L.A. Sheshenya 
 
 Sumy State University, 2, Rymsky Korsakov Str., 40007 Sumy, Ukraine 
 
(Received 23 June 2012; revised manuscript received 29 June 2012; published online 12 August 2012) 
 
The paper deals with the methods of forming three-layer structures by layer condensation of nanoscale 
films Ni, Fe and V.  Investigated the magnetoresistive properties of the samples as well as their depend-
ence on annealing temperature and the thickness of nonmagnetic layer. The correlation of magnetore-
sistance effect  with structural-phase state of film system and its components are defined.  
 
Keywords: Phase composition, Three-layer film systems, Magnetoresistance, Size dependence. 
 
 PACS numbers: 68.55.J, 72.15.Eb, 72.15.Lh, 72.15.Qm  
 
 
1. INTRODUCTION 
 
The development of modern nanoelectronics is close-
ly connected with new technologies of magnetic memory 
devices, intelligent sensors and transmitters. From the 
practical point of using of huge magnetoresistive effect 
(MRE) it is important to find the materials which will 
provide as large values of magnetoresistive ratio as 
possible (R – Rs)/R,  (where R - maximum  resistance of 
the  sample in the magnetic field, Rs - resistance at 
saturation) [1-5]. The high level of minimization of film 
elements requires taking into account the displays of 
their different kinds of size effects [6, 7]. Thus, the limi-
tation of geometrical dimensions of the film and/or crys-
talline grains causes the reduction in the mean length 
of free path of electric current carriers. In addition spin-
dependent scattering of electrons in antiparallel mag-
netic moments of individual ferromagnetic layers or 
magnetic moments of granules or impurity atoms ap-
pear in magnetic non-uniform film materials.  In the 
heating process of such film samples or the influence of 
the magnetic field additional changes in the mean 
length of free path  of electric current carriers and con-
ductivity appear [8, 9]. Shown the above phenomena 
are manifested in the size dependence of many charac-
teristics as well as magnetoresistance ratio. 
The aim of the study has become the research of 
magnetoresistive properties of three-layer films of 
Ni(50nm)/V(dV)/Ni(10nm) and Fe(40nm)/V(dV)/Fe(10 
nm) (dV =1-16 nm) and detection of  size dependence of 
magnetoresistive effect.  
 
2. EXPERIMENTAL  
 
Thin metal films Ni, Fe, and three-layer systems 
Ni/V/Ni, Fe/V/Fe were obtained by thermal evaporation 
method in the vacuum of 10-3-10-4Pa. The plates of 
amorphous glass ceramics were used as substrates in 
the magnetoresistive studies. Layers deposition of the 
materials  was realized out of two evaporators on the 
heated substrate (350 – 400 K). The thicknesses of some 
layers were defined with the method of quartz resonator 
and also were tested with  the interferometric method. 
The samples were annealed in the temperature range 
from 300 to 800 K. 
Electron microscopy and electron diffraction inves-
tigations were carried out using TEM - 125 k 
Magnetoresistive characteristics were determined 
at the room temperature in the alternating external 
magnetic field with  induction from 0 to 600 mT.  
The magnetoresistance was measured for the follow-
ing geometries:- longitudinal, when the vector of magnetic 
induction B is collinear to the  direction of  current;- 
transverse when vector B lies in the plane of the sample 
and it is perpendicular to the direction of current; - per-
pendicular when vector B is perpendicular both to the 
plane of the sample and the direction of  current. 
 
3. RESULTS AND DISCUSSION 
 
State diagram of Ni-V in the range of high tempera-
tures is rather complex and characterized by the pres-
ence of intermediate phases. Two-layer films  on the 
basis of Ni and V in the unannealed  state had phase 
composition bcc-V + fcc-Ni. The lattice parameter  
a = 0.304 nm (film V) and a = 0.351 nm (film Ni), which 
is close to the lattice parameters of single-layer films and 
bulk samples V and Ni. Note, that grains size of just 
condensed film is 15-20 nm. Annealing at the tempera-
ture of T<700 K does not make changes the phase com-
position of the samples and noticeable processes of re-
crystallization. In the films annealed  at the tempera-
ture of 700 ≤ T<800 K, there is a slight increase in the 
lattice parameter of Ni  to the value a = 0.353 nm and 
the decrease in the lattice parameter of V to the value  
a = 0.301 nm.  
All the samples of Ni(50nm)/V(dV)/Ni(10nm)  were ob-
tained under identical technological conditions. Electron 
diffraction and electron microscopy investigations con-
firmed that all the thin film systems had the phase com-
position of bcc-V + fcc-Ni, the polycrystalline structure. 
Experimental studies of magnetoresistive proper-
ties of thin film systems have shown that the unan-
nealed samples with vanadium layer thickness of 
dV < 3 nm had anisotropic magnetoresistance, and 
magnetoresistive hysteresis loops for such systems are 
similar to the corresponding loops for  single layer films 
of ferromagnetic metals (Ni, Fe). The value of the longi-
tudinal and transverse magnetoresistance (MR) does 
not exceed 0.01-0.05 %. Annealing of these samples at 
the temperature of T = 600-650 K is accompanied by a 
slight increase of value MR. 
The absolute values MR of unannealed samples 
with the thickness of nonmagnetic layer dv = 3-11 nm 
are an order of magnitude larger than the previous 
ones, and significantly depend on the phase composi-
tion and concentration of the components of the film 
 V.V. BIBIK, T.M. GRICHANOVSKAYA, A.S. GRISCHUK, L.A. SHESHENYA PROC. NAP 1, 03TF18 (2012) 
 
 
03TF18-2 
system. In the samples where it could  avoid the for-
mation of solid solution, MR grows with increasing an-
nealing temperature and for the films annealed at 650 
K is 0.2-0.6% for the longitudinal and 0.1-0.5% for the 
perpendicular MR.  
For the film systems with concentration of CNi=86-
88 at. % observed isotropy of the magnetoresistive prop-
erties, which is in reduction of electrical resistance in 
the magnetic field, regardless of the geometry of the 
taken measurements, what can be considered one of the 
signs of giant magnetoresistance [1-5].  
The important feature of magnetic nanostructures 
is an oscillation of the exchange link between the fer-
romagnetic layers, depending on the thickness of the 
nonmagnetic layer, which in its turn leads to oscillations 
of magnetic and magnetoresistive properties of the film 
structures. Some of the important characteristics that 
give qualitative information on the behavior of the film 
sample in the process of reversal of magnetization is the 
coercive force (Hc) and the saturation field (Hs). Since 
the valuea Hc determined by the  magnetoresistive loops 
do not coincide with  the values defined by the magnetic 
hysteresis loops, a number of  authors  suggested, by 
analogy with the Hc and Hs, to use the induction of the 
magnetic field required to complete demagnetization of 
the sample (Bc) and saturation induction (Bs).[9]. The 
results of the influence of the indirect exchange link be-
tween ferromagnetic layers of Ni on the value of the co-
ercive force of Ni(50nm)/V(dV)/Ni(20nm) is illustrated in 
Fig. 1. Maxima of demagnetization induction Bc were 
observed at dv ≈ 3 nm and dv ≈11 nm , which corre-
sponded to the maxima of the saturation induction Bs, 
i.e, one can talk about the antiferromagnetic link of fer-
romagnetic layers of Ni in these film systems. 
The system Fe-V is characterized by continuous sol-
ubility in the liquid and solid states, so it was rather 
difficult to get the systems Fe(40 nm)/V(dV)/Fe(10 nm). 
In the samples with dV < 10 nm the presence of vanadi-
um wasn’t revealed by electron diffraction investigation, 
and the Fe lattice parameter was a = 0,289 nm. In the 
samples with dV = 10-12 nm the calculation   of electron 
diffraction showed that the lattice parameter of Fe did 
not change, and the lattice parameter of V is a = 0.302 
nm. Annealing at the temperature of 650 K did not 
change the phase state and the lattice parameters. The 
analysis of  crystal structure showed that all the sam-
ples in the unannealed state are nano-dispersive  with 
an average crystallite size of less than 5 nm. Annealing 
at the temperature of 650-700 K results in slight re-
crystallization processes: it the average crystallite size 
increases to 5-10 nm.  
Anisotropy of field dependence in the systems with 
layers dv < 2 nm turned out to be  similar to the films 
of Fe with dominance of the value MR in the  longitu-
dinal geometry in comparison with other geometries. 
For three-layer films systems with the concentra-
tion CFe = 83-85 at. % is observed isotropy of the mag-
netoresistive properties. The reduction of the electrical 
resistance in the magnetic field was observed regard-
less of the geometry of the measurements. 
The feature of the samples Fe (40 nm) / V (dv) / Fe 
(10 nm)  is that the highest values of MR correspond to  
transverse and perpendicular geometries up to (0,12-
0,14%), whereas for the longitudinal geometry magne-
toresistive ratio is 0,03-0, 06 %, or not at all. 
d
V
,nm0 2 4 6 8 10 12 14
B
C
 , mТ
20
40
60
80
a
d
V
,nm0 2 4 6 8 10 12 14
BS , mT
200
300
400
500
b
  
 
Fig. 1 – The dependence of the demagnetization induction (a) 
and saturation induction (b) from the thickness of the layer V 
of film system  Ni(50nm)/V(dv)/Ni(10nm) unannealed (0) and 
annealed (Δ) at 650 K 
 
Field dependence typical for the spin-valve struc-
ture could be obtained for the sample 
Fe(40)/V(10)/Fe(12) in transverse geometry (Fig.2). The 
presence of a horizontal section on the dependence of 
ΔR/Rs on vector B shows the independent reversal of 
magnetization of  the upper and lower layers.  
 
В, mТ-400 -200 0 200 400
R/Rs,
-0,04
-0,02
0,00
0,02
0,04
 
 
Fig. 2 – Field dependence of the magnetoresistance of Fe (40 
nm)/(10 nm)/Fe(10 nm) in the unannealed state 
 
 
4. CONCLUSIONS 
 
The investigation of structural and magnetoresistive 
properties of the film systems Ni(50nm)/V(dV)/Ni(10nm) 
and Fe(40nm)/V(dV)/Fe(10 nm) (dV =1-16 nm) was car-
ried out. It was shown that at annealing of the systems 
in the temperature range 300-650 K, they retain their 
structural and phase stability. These systems 
Fe(40nm)/V(dV)/Fe(10 nm) (dV ≈ 10 nm) have isotropic 
magnetoresistance and  they can be used as the spin-
valve structures. 
 MAGNETORESISTIVE PROPERTIES OF THREE-LAYER SYSTEMS… PROC. NAP 1, 03TF18 (2012) 
 
 
 03TF18-3  
REFERENCES 
 
1. U. Hartman, Magnetic Multilayers and Giant Magnetore-
sistance: Fundamentals and Industrial Applications (Ber-
lin; Heidelberg; New York: Springer-Verlag: 2000). 
2. T.V. Ustinov, A.B. Rinkevich, L.N. Romashev et al., Tech. 
Phys. 74, 94 (2004). 
3. A.N. Stetsenko, V. Samofalov, V. Zorchenko, JETP Lett. 
64, 346 (1996). 
4. F.S. Bergeret, A.F. Volkov, K.B. Efetov, Rev. Mod. Phys. 
77, 1321 (2005). 
5. A.B.Svalov, P.A.Savin, G.Kurland, et al., Tech. Phys. 72, 
54 (2002). 
6. V. Yudyntsev, Electronics: science, technology, business, 1, 
52 (2008). 
7. I.A. Garifulin, N. Garifyanov, R.I. Salikhov, Phase Transi-
tions, Ordered States and New Materials 1, 1 (2006). 
8. A.P. Boltaev, F.A.Pudonyn, I.A.Sherstnyov, Phys. Solid 
State 53, 892 (2011). 
9. O.V. Synashenko, D.N. Kondrahova, I.Yu. Protsenco,  
J. Nano- Electron. Phys. 2 No4, 96 (2010). 
 


English

Magnetoresistive Properties of Three-Layer Systems on the Basis of Thin Metal Films Fe and V or Ni and V

Electronic Sumy State University Institutional Repository

PROCEEDINGS OF THE INTERNATIONAL CONFERENCE NANOMATERIALS: APPLICATIONS AND PROPERTIES Vol. 1 No 3, 03TF18(3pp) (2012)   2304-1862/2012/1(3)03TF18(3) 03TF18-1  2012 Sumy State University Magnetoresistive Properties of Three-Layer Systems on the Basis of Thin Metal Films  Fe and V or Ni and V  V.V. Bibik, T.M. Grichanovskaya, A.S. Grischuk, L.A. Sheshenya   Sumy State University, 2, Rymsky Korsakov Str., 40007 Sumy, Ukraine  (Received 23 June 2012; revised manuscript received 29 June 2012; published online 12 August 2012)  The paper deals with the methods of forming three-layer structures by layer condensation of nanoscale films Ni, Fe and V.  Investigated the magnetoresistive properties of the samples as well as their depend-ence on annealing temperature and the thickness of nonmagnetic layer. The correlation of magnetore-sistance effect  with structural-phase state of film system and its components are defined.   Keywords: Phase composition, Three-layer film systems, Magnetoresistance, Size dependence.   PACS numbers: 68.55.J, 72.15.Eb, 72.15.Lh, 72.15.Qm    1. INTRODUCTION  The development of modern nanoelectronics is close-ly connected with new technologies of magnetic memory devices, intelligent sensors and transmitters. From the practical point of using of huge magnetoresistive effect (MRE) it is important to find the materials which will provide as large values of magnetoresistive ratio as possible (R – Rs)/R,  (where R - maximum  resistance of the  sample in the magnetic field, Rs - resistance at saturation) [1-5]. The high level of minimization of film elements requires taking into account the displays of their different kinds of size effects [6, 7]. Thus, the limi-tation of geometrical dimensions of the film and/or crys-talline grains causes the reduction in the mean length of free path of electric current carriers. In addition spin-dependent scattering of electrons in antiparallel mag-netic moments of individual ferromagnetic layers or magnetic moments of granules or impurity atoms ap-pear in magnetic non-uniform film materials.  In the heating process of such film samples or the influence of the magnetic field additional changes in the mean length of free path  of electric current carriers and con-ductivity appear [8, 9]. Shown the above phenomena are manifested in the size dependence of many charac-teristics as well as magnetoresistance ratio. The aim of the study has become the research of magnetoresistive properties of three-layer films of Ni(50nm)/V(dV)/Ni(10nm) and Fe(40nm)/V(dV)/Fe(10 nm) (dV =1-16 nm) and detection of  size dependence of magnetoresistive effect.   2. EXPERIMENTAL   Thin metal films Ni, Fe, and three-layer systems Ni/V/Ni, Fe/V/Fe were obtained by thermal evaporation method in the vacuum of 10-3-10-4Pa. The plates of amorphous glass ceramics were used as substrates in the magnetoresistive studies. Layers deposition of the materials  was realized out of two evaporators on the heated substrate (350 – 400 K). The thicknesses of some layers were defined with the method of quartz resonator and also were tested with  the interferometric method. The samples were annealed in the temperature range from 300 to 800 K. Electron microscopy and electron diffraction inves-tigations were carried out using TEM - 125 k Magnetoresistive characteristics were determined at the room temperature in the alternating external magnetic field with  induction from 0 to 600 mT.  The magnetoresistance was measured for the follow-ing geometries:- longitudinal, when the vector of magnetic induction B is collinear to the  direction of  current;- transverse when vector B lies in the plane of the sample and it is perpendicular to the direction of current; - per-pendicular when vector B is perpendicular both to the plane of the sample and the direction of  current.  3. RESULTS AND DISCUSSION  State diagram of Ni-V in the range of high tempera-tures is rather complex and characterized by the pres-ence of intermediate phases. Two-layer films  on the basis of Ni and V in the unannealed  state had phase composition bcc-V + fcc-Ni. The lattice parameter  a = 0.304 nm (film V) and a = 0.351 nm (film Ni), which is close to the lattice parameters of single-layer films and bulk samples V and Ni. Note, that grains size of just condensed film is 15-20 nm. Annealing at the tempera-ture of T<700 K does not make changes the phase com-position of the samples and noticeable processes of re-crystallization. In the films annealed  at the tempera-ture of 700 ≤ T<800 K, there is a slight increase in the lattice parameter of Ni  to the value a = 0.353 nm and the decrease in the lattice parameter of V to the value  a = 0.301 nm.  All the samples of Ni(50nm)/V(dV)/Ni(10nm)  were ob-tained under identical technological conditions. Electron diffraction and electron microscopy investigations con-firmed that all the thin film systems had the phase com-position of bcc-V + fcc-Ni, the polycrystalline structure. Experimental studies of magnetoresistive proper-ties of thin film systems have shown that the unan-nealed samples with vanadium layer thickness of dV < 3 nm had anisotropic magnetoresistance, and magnetoresistive hysteresis loops for such systems are similar to the corresponding loops for  single layer films of ferromagnetic metals (Ni, Fe). The value of the longi-tudinal and transverse magnetoresistance (MR) does not exceed 0.01-0.05 %. Annealing of these samples at the temperature of T = 600-650 K is accompanied by a slight increase of value MR. The absolute values MR of unannealed samples with the thickness of nonmagnetic layer dv = 3-11 nm are an order of magnitude larger than the previous ones, and significantly depend on the phase composi-tion and concentration of the components of the film  V.V. BIBIK, T.M. GRICHANOVSKAYA, A.S. GRISCHUK, L.A. SHESHENYA PROC. NAP 1, 03TF18 (2012)   03TF18-2 system. In the samples where it could  avoid the for-mation of solid solution, MR grows with increasing an-nealing temperature and for the films annealed at 650 K is 0.2-0.6% for the longitudinal and 0.1-0.5% for the perpendicular MR.  For the film systems with concentration of CNi=86-88 at. % observed isotropy of the magnetoresistive prop-erties, which is in reduction of electrical resistance in the magnetic field, regardless of the geometry of the taken measurements, what can be considered one of the signs of giant magnetoresistance [1-5].  The important feature of magnetic nanostructures is an oscillation of the exchange link between the fer-romagnetic layers, depending on the thickness of the nonmagnetic layer, which in its turn leads to oscillations of magnetic and magnetoresistive properties of the film structures. Some of the important characteristics that give qualitative information on the behavior of the film sample in the process of reversal of magnetization is the coercive force (Hc) and the saturation field (Hs). Since the valuea Hc determined by the  magnetoresistive loops do not coincide with  the values defined by the magnetic hysteresis loops, a number of  authors  suggested, by analogy with the Hc and Hs, to use the induction of the magnetic field required to complete demagnetization of the sample (Bc) and saturation induction (Bs).[9]. The results of the influence of the indirect exchange link be-tween ferromagnetic layers of Ni on the value of the co-ercive force of Ni(50nm)/V(dV)/Ni(20nm) is illustrated in Fig. 1. Maxima of demagnetization induction Bc were observed at dv ≈ 3 nm and dv ≈11 nm , which corre-sponded to the maxima of the saturation induction Bs, i.e, one can talk about the antiferromagnetic link of fer-romagnetic layers of Ni in these film systems. The system Fe-V is characterized by continuous sol-ubility in the liquid and solid states, so it was rather difficult to get the systems Fe(40 nm)/V(dV)/Fe(10 nm). In the samples with dV < 10 nm the presence of vanadi-um wasn’t revealed by electron diffraction investigation, and the Fe lattice parameter was a = 0,289 nm. In the samples with dV = 10-12 nm the calculation   of electron diffraction showed that the lattice parameter of Fe did not change, and the lattice parameter of V is a = 0.302 nm. Annealing at the temperature of 650 K did not change the phase state and the lattice parameters. The analysis of  crystal structure showed that all the sam-ples in the unannealed state are nano-dispersive  with an average crystallite size of less than 5 nm. Annealing at the temperature of 650-700 K results in slight re-crystallization processes: it the average crystallite size increases to 5-10 nm.  Anisotropy of field dependence in the systems with layers dv < 2 nm turned out to be  similar to the films of Fe with dominance of the value MR in the  longitu-dinal geometry in comparison with other geometries. For three-layer films systems with the concentra-tion CFe = 83-85 at. % is observed isotropy of the mag-netoresistive properties. The reduction of the electrical resistance in the magnetic field was observed regard-less of the geometry of the measurements. The feature of the samples Fe (40 nm) / V (dv) / Fe (10 nm)  is that the highest values of MR correspond to  transverse and perpendicular geometries up to (0,12-0,14%), whereas for the longitudinal geometry magne-toresistive ratio is 0,03-0, 06 %, or not at all. dV,nm0 2 4 6 8 10 12 14BC , mТ20406080adV,nm0 2 4 6 8 10 12 14BS , mT200300400500b   Fig. 1 – The dependence of the demagnetization induction (a) and saturation induction (b) from the thickness of the layer V of film system  Ni(50nm)/V(dv)/Ni(10nm) unannealed (0) and annealed (Δ) at 650 K  Field dependence typical for the spin-valve struc-ture could be obtained for the sample Fe(40)/V(10)/Fe(12) in transverse geometry (Fig.2). The presence of a horizontal section on the dependence of ΔR/Rs on vector B shows the independent reversal of magnetization of  the upper and lower layers.   В, mТ-400 -200 0 200 400R/Rs,-0,04-0,020,000,020,04  Fig. 2 – Field dependence of the magnetoresistance of Fe (40 nm)/(10 nm)/Fe(10 nm) in the unannealed state   4. CONCLUSIONS  The investigation of structural and magnetoresistive properties of the film systems Ni(50nm)/V(dV)/Ni(10nm) and Fe(40nm)/V(dV)/Fe(10 nm) (dV =1-16 nm) was car-ried out. It was shown that at annealing of the systems in the temperature range 300-650 K, they retain their structural and phase stability. These systems Fe(40nm)/V(dV)/Fe(10 nm) (dV ≈ 10 nm) have isotropic magnetoresistance and  they can be used as the spin-valve structures.  MAGNETORESISTIVE PROPERTIES OF THREE-LAYER SYSTEMS… PROC. NAP 1, 03TF18 (2012)    03TF18-3  REFERENCES  1. U. Hartman, Magnetic Multilayers and Giant Magnetore-sistance: Fundamentals and Industrial Applications (Ber-lin; Heidelberg; New York: Springer-Verlag: 2000). 2. T.V. Ustinov, A.B. Rinkevich, L.N. Romashev et al., Tech. Phys. 74, 94 (2004). 3. A.N. Stetsenko, V. Samofalov, V. Zorchenko, JETP Lett. 64, 346 (1996). 4. F.S. Bergeret, A.F. Volkov, K.B. Efetov, Rev. Mod. Phys. 77, 1321 (2005). 5. A.B.Svalov, P.A.Savin, G.Kurland, et al., Tech. Phys. 72, 54 (2002). 6. V. Yudyntsev, Electronics: science, technology, business, 1, 52 (2008). 7. I.A. Garifulin, N. Garifyanov, R.I. Salikhov, Phase Transi-tions, Ordered States and New Materials 1, 1 (2006). 8. A.P. Boltaev, F.A.Pudonyn, I.A.Sherstnyov, Phys. Solid State 53, 892 (2011). 9. O.V. Synashenko, D.N. Kondrahova, I.Yu. Protsenco,  J. Nano- Electron. Phys. 2 No4, 96 (2010).  

https://essuir.sumdu.edu.ua/bitstream/123456789/35069/1/princon_2012_1_3_20.pdf

Magnetoresistive Properties of Three-Layer Systems on the Basis of Thin Metal Films Fe and V or Ni and V

Abstract

Similar works

Full text

Available Versions

SocioEconomic Challenges Journal (Sumy State University)

Electronic Sumy State University Institutional Repository