High-density and uniform-sized Co1-xSnx alloy nanowires have been prepared electrochemically in anodic
aluminum oxide (AAO) templates. This highly ordered arrays of nanowires have magnetic properties
that affect by several agents including Sn concentration in structure of nanowires and annealing process.
The morphologies of the nanowires were obtained by using the scanning electron microscope (SEM). The
measurement of magnetic properties was made using the alternating gradient fors magnetometer (AGFM).
The composition of the Co1-xSnx nanowires was analyzed by EDX. It has been observed that these properties
were changed significantly with increasing of Sn content in nanowires. Also the affect of annealing
temperature, up to 575˚C, on the magnetic properties and microstructure of as-prepared nanowires have
been investigated.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3534

Khorshidi, M.

Najafi, M.

Rafati, A.A.

SocioEconomic Challenges Journal (Sumy State University)

PROCEEDINGS OF THE INTERNATIONAL CONFERENCE NANOMATERIALS: APPLICATIONS AND PROPERTIES 
Vol. 1 No 4, 04MFPN07(3pp) (2012) 
 
 
2304-1862/2012/1(4)04MFPN07(3) 04MFPN07-1  2012 Sumy State University 
Synthesis and Characterization of Co1-xSnx Magnetic Nanowires 
 
M. Najafi1,*, M. Khorshidi2,†, A.A. Rafati2,‡ 
 
1 Department of Materials Engineering, Hamedan University of Technology (HUT), Hamedan, Iran 
2 Department of Physical Chemistry, Faculty of Chemistry, Bu-Ali Sina University, P.O.Box 65174, Hamedan, Iran 
 
(Received 19 June 2012; published online 23 August 2012) 
 
High-density and uniform-sized Co1-xSnx alloy nanowires have been prepared electrochemically in an-
odic aluminum oxide (AAO) templates. This highly ordered arrays of nanowires have magnetic properties 
that affect by several agents including Sn concentration in structure of nanowires and annealing process. 
The morphologies of the nanowires were obtained by using the scanning electron microscope (SEM). The 
measurement of magnetic properties was made using the alternating gradient fors magnetometer (AGFM). 
The composition of the Co1-xSnx nanowires was analyzed by EDX. It has been observed that these proper-
ties were changed significantly with increasing of Sn content in nanowires. Also the affect of annealing 
temperature, up to 575˚C, on the magnetic properties and microstructure of as-prepared nanowires have 
been investigated. 
 
Keywords: Nanowire, AAO template, Magnetic property, Annealing process. 
 
  PACS numbers: 75.75.Cd, 78.67.Uh 
 
 
                                                          
* mojgannajafi1@gmail.com 
† monakhorshidi@gmail.com 
‡ rafati_aa@yahoo.com 
1. INTRODUCTION 
 
Recently, one-dimensional and quasi-one-
dimensional nanos- tructured materials have attracted 
considerable interest because of their applications in 
optics and high-density perpendicular magnetic record-
ing media and much effort has been expended on the 
synthesis of these materials. The fabrication of magnet-
ic nanowire arrays has received much attention due to 
their potential utilization in high-density magnetic 
recording media. Anodized aluminum oxide (AAO) has 
been extensively used in the past few years as an easy 
way to prepare nanowire by electrodeposition [1]. Anod-
ic oxidation process was happened via the high-purity 
aluminum foil, through process treatment in acid solu-
tion prepared in condition including low pH value and 
temperature of electrolyte solution. 
Templates contain a hexagonally packed two-
dimensional (2D) array of cylindrical pores with a uni-
form size that was very suitable template for fabricat-
ing nanowires [2]. 
Recently, ferromagnetic-nonmagnetic alloy systems 
have attracted much attention in order to improve the 
magnetic properties of nanowires. Alloy nanowires 
were normally electrodeposited via AC electerodeposi-
tion which requires a less complex sample preparation 
process. In present work, the Co1-xSnx alloy nanowires 
have been fabricated in AAO template by AC electro-
deposition. The magnetic properties of Co nanowires 
that affect by addition of Sn concentration and anneal-
ing process up to 575˚C have been investigated [2, 3].  
 
2. EXPERIMENTAL 
 
Ordered AAO templates were prepared via a two-
step anodization process in sulfuric acid solution 
which has been reported in detail in other works [2]. 
On next stage, the nanochannels were filled with al-
loys of Co1-xSnx electrodeposited from an aqueous elec-
trolyte (pH in range 4-4.3) consist of CoSO4.7H2O, 
SnSO4 and NaC6H11O7. The Sn content of the nan-
owires was adjusted by varying ions concentration in 
the electrolyte solution. The co-electrodeposition of 
Co2+ and Sn2+ ions in the AAO template was per-
formed by using a standard double electrode bath and 
AC sine wave (VP-P  30V) at room temperature. Vary-
ing ion concentrations in the solution were utilized for 
producing alloy nanowires with different concentra-
tion of Sn in their structures. Samples were made 
including pure Co nanowires and Co0.99Sn0.01, 
Co0.98Sn0.02, Co0.97Sn0.03, Co0.96Sn0.04, Co0.95Sn0.05, 
Co0.85Sn0.15 alloy nanowires. After producing alloy 
nanowires via co-electrodeposition, these samples 
were annealed at different temperature (200, 300, 
400, 450, 500, 550 and 575˚C) 
 
3. RESULTS AND DISCUSSION 
 
3.1 Co and Sn Content 
 
A typical top view SEM micrograph of a pore struc-
ture after preparation via two step anodization was 
shown in Fig. 1. The SEM image of Co0.95Sn0.05 alloy 
nanowires is shown in Fig. 2 after removal AAO tem-
plate with NaOH solution. 
Fig. 3 is an EDX pattern that demonstrates the el-
emental composition of a typical nanowire system. The 
inset is the curve that compares between Sn concentra-
tion in nanowire structures and SN2+ concentration in 
electrolyte solution. As seen the Sn content in the nan-
owires have a nonlinear relation to the ionic concentra-
tion of Sn in the electrolyte. The amount of Sn in the 
nanowires significantly rises with increasing the Sn2+ 
concentration in the electrolyte, revealing that Sn is de-
posit much faster than Co. Therefore co-electrodeposition 
of this alloy nanowires are an unnormal electrodeposi-
 M. NAJAFI, M. KHORSHIDI, , A.A. RAFATI PROC. NAP 1, 04MFPN07 (2012) 
 
 
04MFPN07-2 
tion. On the other sight, due to non-magnetic of Sn, the 
magnetic properties of nanowires have downward trend 
with increasing the amount of Sn. 
 
 
 
Fig. 1 – A typical top view SEM micrograph of AAO template 
preparing with high-density array of nanopores  
 
 
 
Fig. 2 – SEM image of the Co0.95Sn0.05 nanowires were re-
leased from the AAO template 
 
 
 
Fig. 3 – A typical EDX result of Co0.85Sn0.15 nanowires. Inset 
show the variation of Sn content in the content of alloy  nan-
owires versus ionic concentration of Sn in the electrolyte solu-
tion measuring by EDX. 
 
3.2 Effect of the Sn Content and Annealing 
 
Fig. 4 brightly illustrated how Sn concentration and 
annealing process up to 575˚C can affect on magnetic co-
ercivity of alloy nanowires. With surveying this curve, 
decreasing in Hc values because of increasing in Sn con-
centration is seen. On the other hand annealing process 
rise the Hc value of alloy nanowires especially for sample 
of Co0.99Sn0.01 Co nanowires do not have considerable in-
creasing after per stag of annealing process but all alloy 
nanowires steadily rise is shown. To further investigate 
about the effect of the Sn content on the structure of nan-
owire, the crystal structure of samples was studied. The 
XRD pattern of nanowire arrays are shown in Fig. 5. As 
seen, the as deposit Co0.99Sn0.01 and Co0.97Sn0.03 alloy nan-
owires revealing an amorphous shape which  annealing 
up to 575˚C does not varied the crystal structure of alloy 
nanowires. As a result, the shape anisotropy is a more 
important agent in determining of the magnetic properties 
of nanowires. While annealing process was done the Sn 
melted due to low melting temperature of this metal 
(about 231.93˚C). Finally in the next step nanowires 
cooled slowly improving the tension in structure of alloy 
nanowires. So shape anisotropy of these nanowires were 
improved [2, 4]. 
 
0 1 2 3 4 5
500
600
700
800
900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
2000
2100
 0
 200
 300
 400
 450
 500
 550
 575
 
 
Fig. 4 – The effect of annealing temperature on the Hc value of 
Co1-xSnx of nanowires for x= 0, 0.1, 0.2, 0.3, 0.4, and 0.05 
 
30 40 50 60 70 80
0
10
20
30
40
50
60
70
80
90
100
 
 
Fig. 5 – The XRD patterns of the as Co0.99Sn0.01 and Co0.97Sn0.03 
samples before annealing and after annealing up to 575˚C 
 
4. CONCLUSION 
 
To summarise, highly ordered nanowire arrays of 
Co1-xSnx with high aspect ratio were fabricated by co-
electrodeposition of Co and Sn in to pores of AAO tem-
plates. Furthermore electrodeposition of Co2+ and Sn2+ in 
structure of alloy nanowires is an unnormal co-
electrodeposition. The effect of Sn concentration in the 
content of array nanowires and annealing process on the 
-2 0 2 4 6 8 10 12 14 16
0
20
40
60
80
 
 SYNTHESIS AND CHARACTERIZATION OF CO1-XSNX… PROC. NAP 1, 04MFPN07 (2012) 
 
 
04MFPN07-3 
magnetic properties of the deposited nanowires was in-
vestigated. It is found that Hc values of alloy nanowires 
are dropped with addition Sn in structure of nanowire. 
Amount of alloy nanowires coercivity  risen after anneal-
ing process via improving shape anisotropy.  
AKNOWLEDGEMENT 
 
The authors are grateful for the financial support 
from the Grant Research Councils of Bu-Ali Sina and 
HUT Universities. 
 
 
REFERENCES 
 
1. W. Li, G.A. Jones, Y. Peng, T.H. Shen, J. Appl. Phys. 97, 
104306 (2005). 
2. M. Koohbor, S. Soltanian, M. Najafi, P. Servati, J. Mater. 
Chem. Phys. 131, No728,734 (2012). 
3. A.I. Gapin, X.R. Ye, J.F. Aubuchon, L.H. Chen, Y.J. Tang, 
S. Jin, J. Appl. Phys. 99, 08G902 (2006). 
4. M.T. Rahman, R.K. Dumas, N. Ebagi, N.N. Shams, 
Y.C. Wu, K. Liu, C.H. Lai, J. Appl. Phys. Lett. 94, 042507 
(2009). 
 


Synthesis and Characterization of Co1-xSnx Magnetic Nanowires

Electronic Sumy State University Institutional Repository

PROCEEDINGS OF THE INTERNATIONAL CONFERENCE NANOMATERIALS: APPLICATIONS AND PROPERTIES Vol. 1 No 4, 04MFPN07(3pp) (2012)   2304-1862/2012/1(4)04MFPN07(3) 04MFPN07-1  2012 Sumy State University Synthesis and Characterization of Co1-xSnx Magnetic Nanowires  M. Najafi1,*, M. Khorshidi2,†, A.A. Rafati2,‡  1 Department of Materials Engineering, Hamedan University of Technology (HUT), Hamedan, Iran 2 Department of Physical Chemistry, Faculty of Chemistry, Bu-Ali Sina University, P.O.Box 65174, Hamedan, Iran  (Received 19 June 2012; published online 23 August 2012)  High-density and uniform-sized Co1-xSnx alloy nanowires have been prepared electrochemically in an-odic aluminum oxide (AAO) templates. This highly ordered arrays of nanowires have magnetic properties that affect by several agents including Sn concentration in structure of nanowires and annealing process. The morphologies of the nanowires were obtained by using the scanning electron microscope (SEM). The measurement of magnetic properties was made using the alternating gradient fors magnetometer (AGFM). The composition of the Co1-xSnx nanowires was analyzed by EDX. It has been observed that these proper-ties were changed significantly with increasing of Sn content in nanowires. Also the affect of annealing temperature, up to 575˚C, on the magnetic properties and microstructure of as-prepared nanowires have been investigated.  Keywords: Nanowire, AAO template, Magnetic property, Annealing process.    PACS numbers: 75.75.Cd, 78.67.Uh                                                             * mojgannajafi1@gmail.com † monakhorshidi@gmail.com ‡ rafati_aa@yahoo.com 1. INTRODUCTION  Recently, one-dimensional and quasi-one-dimensional nanos- tructured materials have attracted considerable interest because of their applications in optics and high-density perpendicular magnetic record-ing media and much effort has been expended on the synthesis of these materials. The fabrication of magnet-ic nanowire arrays has received much attention due to their potential utilization in high-density magnetic recording media. Anodized aluminum oxide (AAO) has been extensively used in the past few years as an easy way to prepare nanowire by electrodeposition [1]. Anod-ic oxidation process was happened via the high-purity aluminum foil, through process treatment in acid solu-tion prepared in condition including low pH value and temperature of electrolyte solution. Templates contain a hexagonally packed two-dimensional (2D) array of cylindrical pores with a uni-form size that was very suitable template for fabricat-ing nanowires [2]. Recently, ferromagnetic-nonmagnetic alloy systems have attracted much attention in order to improve the magnetic properties of nanowires. Alloy nanowires were normally electrodeposited via AC electerodeposi-tion which requires a less complex sample preparation process. In present work, the Co1-xSnx alloy nanowires have been fabricated in AAO template by AC electro-deposition. The magnetic properties of Co nanowires that affect by addition of Sn concentration and anneal-ing process up to 575˚C have been investigated [2, 3].   2. EXPERIMENTAL  Ordered AAO templates were prepared via a two-step anodization process in sulfuric acid solution which has been reported in detail in other works [2]. On next stage, the nanochannels were filled with al-loys of Co1-xSnx electrodeposited from an aqueous elec-trolyte (pH in range 4-4.3) consist of CoSO4.7H2O, SnSO4 and NaC6H11O7. The Sn content of the nan-owires was adjusted by varying ions concentration in the electrolyte solution. The co-electrodeposition of Co2+ and Sn2+ ions in the AAO template was per-formed by using a standard double electrode bath and AC sine wave (VP-P  30V) at room temperature. Vary-ing ion concentrations in the solution were utilized for producing alloy nanowires with different concentra-tion of Sn in their structures. Samples were made including pure Co nanowires and Co0.99Sn0.01, Co0.98Sn0.02, Co0.97Sn0.03, Co0.96Sn0.04, Co0.95Sn0.05, Co0.85Sn0.15 alloy nanowires. After producing alloy nanowires via co-electrodeposition, these samples were annealed at different temperature (200, 300, 400, 450, 500, 550 and 575˚C)  3. RESULTS AND DISCUSSION  3.1 Co and Sn Content  A typical top view SEM micrograph of a pore struc-ture after preparation via two step anodization was shown in Fig. 1. The SEM image of Co0.95Sn0.05 alloy nanowires is shown in Fig. 2 after removal AAO tem-plate with NaOH solution. Fig. 3 is an EDX pattern that demonstrates the el-emental composition of a typical nanowire system. The inset is the curve that compares between Sn concentra-tion in nanowire structures and SN2+ concentration in electrolyte solution. As seen the Sn content in the nan-owires have a nonlinear relation to the ionic concentra-tion of Sn in the electrolyte. The amount of Sn in the nanowires significantly rises with increasing the Sn2+ concentration in the electrolyte, revealing that Sn is de-posit much faster than Co. Therefore co-electrodeposition of this alloy nanowires are an unnormal electrodeposi- M. NAJAFI, M. KHORSHIDI, , A.A. RAFATI PROC. NAP 1, 04MFPN07 (2012)   04MFPN07-2 tion. On the other sight, due to non-magnetic of Sn, the magnetic properties of nanowires have downward trend with increasing the amount of Sn.    Fig. 1 – A typical top view SEM micrograph of AAO template preparing with high-density array of nanopores     Fig. 2 – SEM image of the Co0.95Sn0.05 nanowires were re-leased from the AAO template    Fig. 3 – A typical EDX result of Co0.85Sn0.15 nanowires. Inset show the variation of Sn content in the content of alloy  nan-owires versus ionic concentration of Sn in the electrolyte solu-tion measuring by EDX.  3.2 Effect of the Sn Content and Annealing  Fig. 4 brightly illustrated how Sn concentration and annealing process up to 575˚C can affect on magnetic co-ercivity of alloy nanowires. With surveying this curve, decreasing in Hc values because of increasing in Sn con-centration is seen. On the other hand annealing process rise the Hc value of alloy nanowires especially for sample of Co0.99Sn0.01 Co nanowires do not have considerable in-creasing after per stag of annealing process but all alloy nanowires steadily rise is shown. To further investigate about the effect of the Sn content on the structure of nan-owire, the crystal structure of samples was studied. The XRD pattern of nanowire arrays are shown in Fig. 5. As seen, the as deposit Co0.99Sn0.01 and Co0.97Sn0.03 alloy nan-owires revealing an amorphous shape which  annealing up to 575˚C does not varied the crystal structure of alloy nanowires. As a result, the shape anisotropy is a more important agent in determining of the magnetic properties of nanowires. While annealing process was done the Sn melted due to low melting temperature of this metal (about 231.93˚C). Finally in the next step nanowires cooled slowly improving the tension in structure of alloy nanowires. So shape anisotropy of these nanowires were improved [2, 4].  0 1 2 3 4 5500600700800900100011001200130014001500160017001800190020002100 0 200 300 400 450 500 550 575  Fig. 4 – The effect of annealing temperature on the Hc value of Co1-xSnx of nanowires for x= 0, 0.1, 0.2, 0.3, 0.4, and 0.05  30 40 50 60 70 800102030405060708090100  Fig. 5 – The XRD patterns of the as Co0.99Sn0.01 and Co0.97Sn0.03 samples before annealing and after annealing up to 575˚C  4. CONCLUSION  To summarise, highly ordered nanowire arrays of Co1-xSnx with high aspect ratio were fabricated by co-electrodeposition of Co and Sn in to pores of AAO tem-plates. Furthermore electrodeposition of Co2+ and Sn2+ in structure of alloy nanowires is an unnormal co-electrodeposition. The effect of Sn concentration in the content of array nanowires and annealing process on the -2 0 2 4 6 8 10 12 14 16020406080  SYNTHESIS AND CHARACTERIZATION OF CO1-XSNX… PROC. NAP 1, 04MFPN07 (2012)   04MFPN07-3 magnetic properties of the deposited nanowires was in-vestigated. It is found that Hc values of alloy nanowires are dropped with addition Sn in structure of nanowire. Amount of alloy nanowires coercivity  risen after anneal-ing process via improving shape anisotropy.  AKNOWLEDGEMENT  The authors are grateful for the financial support from the Grant Research Councils of Bu-Ali Sina and HUT Universities.   REFERENCES  1. W. Li, G.A. Jones, Y. Peng, T.H. Shen, J. Appl. Phys. 97, 104306 (2005). 2. M. Koohbor, S. Soltanian, M. Najafi, P. Servati, J. Mater. Chem. Phys. 131, No728,734 (2012). 3. A.I. Gapin, X.R. Ye, J.F. Aubuchon, L.H. Chen, Y.J. Tang, S. Jin, J. Appl. Phys. 99, 08G902 (2006). 4. M.T. Rahman, R.K. Dumas, N. Ebagi, N.N. Shams, Y.C. Wu, K. Liu, C.H. Lai, J. Appl. Phys. Lett. 94, 042507 (2009).  

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Synthesis and Characterization of Co1-xSnx Magnetic Nanowires

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