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Polycrystalline Sr2FeMoO6 thin films on Si substrate by pulsed laser deposition for magnetoresistive applications
Materials Letters 118 (2014) 200–203
Contents lists available at ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/matlet
Polycrystalline Sr2FeMoO6 thin films on Si substrate by pulsed laser deposition for magnetoresistive applications Nitu Kumar a,b,c,n, P. Misra c,1, R.K. Kotnala a, Anurag Gaur b, R. Rawat d, R.J. Choudhary d, R.S. Katiyar c a
National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi 110012, India Department of Physics, National Institute of Technology, Kurukshetra 136119, India c Department of Physics, University of Puerto Rico, San Juan, PR 00931, USA d UGC–DAE Consortium for Scientific Research, Khandwa Road, Indore 452001, India b
art ic l e i nf o
a b s t r a c t
Article history: Received 8 November 2013 Accepted 23 November 2013 Available online 6 December 2013
Polycrystalline Sr2FeMoO6 (SFMO) thin films were deposited at different substrate temperatures (500–800 1C) on STO buffered Si (100) substrates by pulsed laser deposition (PLD). Structural analysis shows the single phase formation of polycrystalline SFMO thin films. A large ( 12%) high field magnetoresistance (HFMR) was observed at 5 K in polycrystalline films deposited at 8001C.. First time, we studied the MR effect in polycrystalline SFMO thin films grown on Si substrate, which make them very promising for magnetoresistive and spintronic applications and possibly open the future prospect for their possible integration in microelectronic industries. & 2013 Elsevier B.V. All rights reserved.
Keywords: Thin films Physical vapor deposition X-ray techniques
1. Introduction Intense research activities have been focused on the half-metallic ferromagnets, which are important in spin-based electronic devices and potentially useful for data storage technology. The ferromagnetic Sr2FeMoO6 (SFMO) has drawn a lot of interest in recent years due to its high value of spin polarization and high Curie temperature [1,2]. The magnetic structure has been described as an ordered arrangement of Fe3þ magnetic moments antiferromagnetically coupled to the Mo5 þ moments, resulting in a total saturation magnetic moment of 4mB at low temperature. However, major experimental studies reported the saturation magnetic moment less than this expected value [3,4]. The electronic structure calculations showes that ordered SFMO is half-metallic and exhibits tunneling-type magnetoresistance (MR) even at room temperature. This makes very attractive for room temperature spintronics and magnetoresistive sensor applications [5]. These applications, in practice, are often based on multilayer structures requiring high quality thin films of individual layers. However, due to the stringent requirements and resulting narrow window of deposition parameters, the high-quality growth of SFMO thin films is quite difficult [6,7]. Fabrication of high quality thin films of SFMO is very sensitive to deposition parameters like temperature and atmosphere [7] however, the impurity phases are easily formed [7,8]. n Corresponding author at: National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi 110012, India.Tel.: +91 7838343057; fax: +91 11 45609310. E-mail addresses: [email protected] (N. Kumar), [email protected] (P. Misra). 1 Tel.: þ1 7877514210; fax: þ 1 7877642571.
0167-577X/$ - see front matter & 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.matlet.2013.11.113
Recently Jalili et al. [9] have been deposited the polycrystalline SFMO thin films on Si (100) substrate by PLD technique and studied their structural and magnetic properties. In the present work we explored the magnetoresistance behavior of SFMO thin films besides their structural and magnetic properties. Magnetotransport properties of the polycrystalline SFMO thin films were measured at 300 and 5 K. The present results open up the future prospects of integrating SFMO thin films into the magnetic tunnel junctions as aimed in our recent observation [10].
2. Experiments PLD was used to grow the SFMO thin films on Si (100) substrates at different temperatures (500–800 1C) in vacuum (base pressure of 5 10 6 Torr). The KrF excimer laser operating at 248 nm at 10 Hz repetition rate and fluence of 1.5 J/cm2 was used. Prior to deposition of the SFMO thin films, the STO buffer layer was grown on Si substrate in presence of high purity (99.99%) oxygen at an ambient pressure of 50 mTorr and at 500 1C and subsequently annealed in-situ at 800 1C. The SFMO and STO stoichiometric targets were fabricated in-house through a standard solid state reaction method [11]. The crystalline structure and surface morphology of the films were determined by X-ray diffraction (XRD) and Atomic Force Microscopy (AFM) measurements. The local magnetic moments were measured by Magnetic Field Microscopy (MFM). Magnetization measurements were performed using SQUID–VSM (Quantum Design, USA). Four probe techniques were used to measure the magnetoresistance
N. Kumar et al. / Materials Letters 118 (2014) 200–203
behavior at 300 and 5 K (magnetic field 78 T) by using 8-Tesla Oxford instrument.
3. Results and discussions Fig. 1 show the XRD patterns of SFMO thin films grown on STO buffered Si(100) substrate at four different substrate temperatures (TD).
Fig. 1. X-ray diffraction pattern of SFMO thin films grown on STO buffered Si (100) substrate at elevated temperatures.
201
The film deposited at low temperature (r600 1C) does not produce the stoichiometric SFMO phase and an additional spurious peak of strontium molybdate (SrMoO4) was formed. However, the Secondary impurity phases were commonly observed at low growth temperatures [9,12]. The aforesaid impurity phases completely disappeared, and a single SFMO phase was formed at 700 1C and above. A series of SFMO peaks were observed at 2θ¼31.71, 45.21 and 56.31 corresponding to the (200), (202) and (204) planes respectively of SFMO, which are consistent with the results of SFMO thin films deposited on Si substrate [9]. A notable change in the shifting and sharpening of XRD peaks was observed with increasing growth temperature. This is apparently a consequence of the enhancement in the crystallinity of the SFMO phase with increasing temperature. Fig. 2(a-d) show the corresponding AFM and MFM images for SFMO film grown at 500 and 800 1C respectively. A clear granular nature with uniform distribution of regularly shaped grains with an average size of 100 nm can be seen by the AFM image for the film deposited at 800 1C. The film deposited at 500 1C is comparatively smothered with rms roughness of 4.59 nm compared to 9.04 nm for film deposited at 800 1C. Further to confirm the magnetic ordering in the films, MFM measurements were done over the large 10 10 mm2 sampling area (Fig. 2(c) and (d)). The film deposited at 800 1C clearly reveals ferromagnetic behavior at room temperature. The magnetic domains appear to have an irregular, elongated shape, which is considerably larger than the grain size 100 nm, indicating that the SFMO grains are well connected electromagnetically. However, the film deposited at low temperature 500 1C shows a very low ferromagnetic contrast, which is further supported by SQUID–VSM results. Fig. 3(a) plots the magnetization versus magnetic field (M–H) curves measured at 300 K for all films. The film grown at 500 and
Fig. 2(a-d). AFM and MFM images for the thin film samples grown on Si (100) substrate at low temperature (500 1C) and at high temperature (800 1C) respectively. MFM images obtained at a lift height of 30 nm for a 10 mm 10 mm sampling area at room temperature.
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N. Kumar et al. / Materials Letters 118 (2014) 200–203
Fig. 3. (a) Magnetization versus field loops of all the SFMO thin film at 300 K. (b) MR behavior of all the SFMO thin films at 300 K.
800 1C shows saturation magnetization ( r0.30 and 1.5mB/f.u.) at 300 K, respectively. The analysis of the magnetization measurements reveals that the total magnetization significantly increasing with temperature. The insulating impurity phase and sample inhomogeneities decrease the degree of ferromagnetic longrange order, resulting the decrease in magnetization of film deposited at 5001C.. It is also reported [2,13–15] that the degree of cation ordering (ASD) has a strong reducing effect on the magnetic properties [13,14] and it is linearly dependent upon the growth temperatures. Fig. 3(b) shows the MR behavior for all the thin films at room temperature. The films grown at low temperature exhibit a very small MR effect that was found to be further enhanced with growth temperatures. This effect can be attributed to improvement in the following factors, e.g., grain size, grain connectivity, antisite ordering and crystallinity of the intra-granular material. The strongest negative magnetoresistance effects are observed in films, which have better structural and magnetic properties. Therefore, to understand this phenomena, further magnetoresistance and magnetic measurements were done at low temperature 5 K (Fig. 4(a) and (b)). The polycrystalline SFMO thin film showed almost linear [16,17] type MR behaviors at 300 and 5 K, which contradicts with the low-field MR (LFMR) for the single crystalline thin film [18,19] and bulk polycrystalline SFMO [2,11,20]. Additionally, in our case the magnitude of MR was also found to be much
Fig. 4. (a) MR behavior at 5 K for SFMO thin film grown at 800 1C. (b) Magnetic field dependence of magnetization at 5 K for SFMO thin film grown at 800 1C.
higher (12% at 8 T) as compared to the ( 3.80% MR at 8 T) polycrystalline thin film grown on STO polycrystalline substrate [16]. The typical coercive field obtained from MH and MR at 5 K is found to be 0.05 T and 0.55 T respectively. The observation of higher coercive field for MR curve is consistent with the result of Sarma et al. [21]. However, the two main mechanisms are responsible for magnetoresistance behavior in SFMO materials. The first is ascribed to grain boundaries and even impurity-phase grain boundaries, which lead to the inter-granular tunneling effect [1,11,20]. The second is intra-granular two-dimensional defects which are related to the intrinsic behavior, such as antisite disorder, antiphase boundaries and some domain boundaries [22]. However in our case, the polycrystalline film shows almost linear variation of MR at high field rather than its tendency to saturate. It is expected due to the intra-granular nature of grains, and also related with the antisite disordering between Fe and Mo ions. Since such disordering, [22], creates antiferromagnetic SrFeO3 regions in SFMO, one can expect antiferromagnetic ordering at the grain boundaries in SFMO films is contrast with the ferrimagnetic ordering in SFMO grains. Therefore, we purpose that the linear type MR behavior in our polycrystalline SFMO thin films could be observed due to the intrinsic property and antisite disordering
N. Kumar et al. / Materials Letters 118 (2014) 200–203
effect, which is defined as high field magnetoresistance (HFMR) type behavior as reported in bulk disordered samples [23]. 4. Conclusions The SFMO thin films were deposited at different temperatures ranging from 500 to 800 1C by pulsed laser deposition on STO buffered Si (100) substrates and the linear type MR behavior at 300 and 5 K was observed. The observation of room temperature magnetoresistance in SFMO thin films on Si (100) substrate is very promising and attractive for magnetoresistive and spintronic applications. Acknowledgment The authors acknowledge the financial support from DOE (grant DE-FG02-ER46526). One of the author N. Kumar gratefully acknowledges CSIR, India, for SRF fellowship to carry out this work as a part of his Ph.D. dissertation at NPL, New Delhi and NIT Kurukshetra, India. References [1] Kobayashi KI, Kimura T, Sawada H, Terakura K, Tokura Y. Nature 1998;395:677–80. [2] Sanchez D, Alonso JA, Garcia-Hernandez M, Martinez-Lope MJ, Martinez JL, Mellergard A. Phys Rev B 2002;65:104426–8.
203
[3] Tomioka Y, Okuda T, Okimoto Y, Kumai R, Kobayashi KI, Tokura Y. Phys Rev B 2000;61:422–7. [4] Huang YH, Yamauchi H, Karppinen M. Phys Rev B 2006;74:174418-6. [5] Poddar A, Bhowmik RN, Muthuselvam P, Das N. J Appl Phys 2009;106:0739088. [6] Suominen T, Raittila J, Paturi P. Thin Solid Films 2009;517:5793–7. [7] Paturi P, Metsanoja M, Huhtinen H. Thin Solid Films 2011;519:8047–52. [8] Santiso J, Figueras A, Fraxedas J. Surf Interface Anal 2002;33:676–80. [9] Jalili H, Heinig NF, Leung KT. J Appl Phys 2009;105:034305–6. [10] Kumar N, Misra P, Kotnala RK, Gaur A, Katiyar RS. J Phys D: Appl Phys Acceptance date 04 Dec 2013 (Article ID: D/483608/PAP). [11] Kumar N, Khurana G, Gaur A, Kotnala RK. J Appl Phys 2013;114:053902–5. [12] Bianchini L. Synthesizing and Characterizing Sr2FeMoO6 Bulk and Thin Films. Undergrad Rev 2008;4:65–70. [13] Wang S, Pan H, Zhang X, Lian G, Xion G. Appl Phys Lett 2006;88:121912–3. [14] Singh VN, Majumdar P. Europhys Lett 2011;94:47004–6. [15] Navarro J, Balcells LI, Sandiumenge F, Bibes M, Roig A, Martínez B, et al. J Phys: Condens Matter 2001;13:8481–8. [16] Shinde SR, Ogale SB, Greene RL, Venkatesan T, Tsoi K, Cheong SW, et al. J Appl Phys 2003;93:1605–12. [17] Muduli PK, Budhani RC, Topwal D, Sarma DD. Journal of Physics: Conference Series 2009;150:042132–4. [18] Saloaro M, Majumdar S, Huhtinen H, Paturi P. J Phys: Condens Matter 2012;24:366003–9. [19] Song JH, Park JH, Jeong YH. J Appl Phys 2005;97:046105-3. [20] Kumar N, Pandey V, Gaur A, Kotnala RK. J Appl Phys 2012;112:073925–6. [21] Sarma DD, Ray S, Tanaka K, Kobayashi M, Fujimori A, Sanyal P, et al. Phys Rev Lett 2007;98:157205-4. [22] Garcia-Hernandez M, Martinez JL, Martinez-Lope MJ, Casais MT, Alonso JA. Phys Rev Lett 2001;86:2443–6. [23] Sarma DD, Sampathkumaran EV, Ray S, Nagarajan R, Majumdar S, Kumar A, et al. Solid State Commun 2000;114:465–8.
Contents lists available at ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/matlet
Polycrystalline Sr2FeMoO6 thin films on Si substrate by pulsed laser deposition for magnetoresistive applications Nitu Kumar a,b,c,n, P. Misra c,1, R.K. Kotnala a, Anurag Gaur b, R. Rawat d, R.J. Choudhary d, R.S. Katiyar c a
National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi 110012, India Department of Physics, National Institute of Technology, Kurukshetra 136119, India c Department of Physics, University of Puerto Rico, San Juan, PR 00931, USA d UGC–DAE Consortium for Scientific Research, Khandwa Road, Indore 452001, India b
art ic l e i nf o
a b s t r a c t
Article history: Received 8 November 2013 Accepted 23 November 2013 Available online 6 December 2013
Polycrystalline Sr2FeMoO6 (SFMO) thin films were deposited at different substrate temperatures (500–800 1C) on STO buffered Si (100) substrates by pulsed laser deposition (PLD). Structural analysis shows the single phase formation of polycrystalline SFMO thin films. A large ( 12%) high field magnetoresistance (HFMR) was observed at 5 K in polycrystalline films deposited at 8001C.. First time, we studied the MR effect in polycrystalline SFMO thin films grown on Si substrate, which make them very promising for magnetoresistive and spintronic applications and possibly open the future prospect for their possible integration in microelectronic industries. & 2013 Elsevier B.V. All rights reserved.
Keywords: Thin films Physical vapor deposition X-ray techniques
1. Introduction Intense research activities have been focused on the half-metallic ferromagnets, which are important in spin-based electronic devices and potentially useful for data storage technology. The ferromagnetic Sr2FeMoO6 (SFMO) has drawn a lot of interest in recent years due to its high value of spin polarization and high Curie temperature [1,2]. The magnetic structure has been described as an ordered arrangement of Fe3þ magnetic moments antiferromagnetically coupled to the Mo5 þ moments, resulting in a total saturation magnetic moment of 4mB at low temperature. However, major experimental studies reported the saturation magnetic moment less than this expected value [3,4]. The electronic structure calculations showes that ordered SFMO is half-metallic and exhibits tunneling-type magnetoresistance (MR) even at room temperature. This makes very attractive for room temperature spintronics and magnetoresistive sensor applications [5]. These applications, in practice, are often based on multilayer structures requiring high quality thin films of individual layers. However, due to the stringent requirements and resulting narrow window of deposition parameters, the high-quality growth of SFMO thin films is quite difficult [6,7]. Fabrication of high quality thin films of SFMO is very sensitive to deposition parameters like temperature and atmosphere [7] however, the impurity phases are easily formed [7,8]. n Corresponding author at: National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi 110012, India.Tel.: +91 7838343057; fax: +91 11 45609310. E-mail addresses: [email protected] (N. Kumar), [email protected] (P. Misra). 1 Tel.: þ1 7877514210; fax: þ 1 7877642571.
0167-577X/$ - see front matter & 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.matlet.2013.11.113
Recently Jalili et al. [9] have been deposited the polycrystalline SFMO thin films on Si (100) substrate by PLD technique and studied their structural and magnetic properties. In the present work we explored the magnetoresistance behavior of SFMO thin films besides their structural and magnetic properties. Magnetotransport properties of the polycrystalline SFMO thin films were measured at 300 and 5 K. The present results open up the future prospects of integrating SFMO thin films into the magnetic tunnel junctions as aimed in our recent observation [10].
2. Experiments PLD was used to grow the SFMO thin films on Si (100) substrates at different temperatures (500–800 1C) in vacuum (base pressure of 5 10 6 Torr). The KrF excimer laser operating at 248 nm at 10 Hz repetition rate and fluence of 1.5 J/cm2 was used. Prior to deposition of the SFMO thin films, the STO buffer layer was grown on Si substrate in presence of high purity (99.99%) oxygen at an ambient pressure of 50 mTorr and at 500 1C and subsequently annealed in-situ at 800 1C. The SFMO and STO stoichiometric targets were fabricated in-house through a standard solid state reaction method [11]. The crystalline structure and surface morphology of the films were determined by X-ray diffraction (XRD) and Atomic Force Microscopy (AFM) measurements. The local magnetic moments were measured by Magnetic Field Microscopy (MFM). Magnetization measurements were performed using SQUID–VSM (Quantum Design, USA). Four probe techniques were used to measure the magnetoresistance
N. Kumar et al. / Materials Letters 118 (2014) 200–203
behavior at 300 and 5 K (magnetic field 78 T) by using 8-Tesla Oxford instrument.
3. Results and discussions Fig. 1 show the XRD patterns of SFMO thin films grown on STO buffered Si(100) substrate at four different substrate temperatures (TD).
Fig. 1. X-ray diffraction pattern of SFMO thin films grown on STO buffered Si (100) substrate at elevated temperatures.
201
The film deposited at low temperature (r600 1C) does not produce the stoichiometric SFMO phase and an additional spurious peak of strontium molybdate (SrMoO4) was formed. However, the Secondary impurity phases were commonly observed at low growth temperatures [9,12]. The aforesaid impurity phases completely disappeared, and a single SFMO phase was formed at 700 1C and above. A series of SFMO peaks were observed at 2θ¼31.71, 45.21 and 56.31 corresponding to the (200), (202) and (204) planes respectively of SFMO, which are consistent with the results of SFMO thin films deposited on Si substrate [9]. A notable change in the shifting and sharpening of XRD peaks was observed with increasing growth temperature. This is apparently a consequence of the enhancement in the crystallinity of the SFMO phase with increasing temperature. Fig. 2(a-d) show the corresponding AFM and MFM images for SFMO film grown at 500 and 800 1C respectively. A clear granular nature with uniform distribution of regularly shaped grains with an average size of 100 nm can be seen by the AFM image for the film deposited at 800 1C. The film deposited at 500 1C is comparatively smothered with rms roughness of 4.59 nm compared to 9.04 nm for film deposited at 800 1C. Further to confirm the magnetic ordering in the films, MFM measurements were done over the large 10 10 mm2 sampling area (Fig. 2(c) and (d)). The film deposited at 800 1C clearly reveals ferromagnetic behavior at room temperature. The magnetic domains appear to have an irregular, elongated shape, which is considerably larger than the grain size 100 nm, indicating that the SFMO grains are well connected electromagnetically. However, the film deposited at low temperature 500 1C shows a very low ferromagnetic contrast, which is further supported by SQUID–VSM results. Fig. 3(a) plots the magnetization versus magnetic field (M–H) curves measured at 300 K for all films. The film grown at 500 and
Fig. 2(a-d). AFM and MFM images for the thin film samples grown on Si (100) substrate at low temperature (500 1C) and at high temperature (800 1C) respectively. MFM images obtained at a lift height of 30 nm for a 10 mm 10 mm sampling area at room temperature.
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N. Kumar et al. / Materials Letters 118 (2014) 200–203
Fig. 3. (a) Magnetization versus field loops of all the SFMO thin film at 300 K. (b) MR behavior of all the SFMO thin films at 300 K.
800 1C shows saturation magnetization ( r0.30 and 1.5mB/f.u.) at 300 K, respectively. The analysis of the magnetization measurements reveals that the total magnetization significantly increasing with temperature. The insulating impurity phase and sample inhomogeneities decrease the degree of ferromagnetic longrange order, resulting the decrease in magnetization of film deposited at 5001C.. It is also reported [2,13–15] that the degree of cation ordering (ASD) has a strong reducing effect on the magnetic properties [13,14] and it is linearly dependent upon the growth temperatures. Fig. 3(b) shows the MR behavior for all the thin films at room temperature. The films grown at low temperature exhibit a very small MR effect that was found to be further enhanced with growth temperatures. This effect can be attributed to improvement in the following factors, e.g., grain size, grain connectivity, antisite ordering and crystallinity of the intra-granular material. The strongest negative magnetoresistance effects are observed in films, which have better structural and magnetic properties. Therefore, to understand this phenomena, further magnetoresistance and magnetic measurements were done at low temperature 5 K (Fig. 4(a) and (b)). The polycrystalline SFMO thin film showed almost linear [16,17] type MR behaviors at 300 and 5 K, which contradicts with the low-field MR (LFMR) for the single crystalline thin film [18,19] and bulk polycrystalline SFMO [2,11,20]. Additionally, in our case the magnitude of MR was also found to be much
Fig. 4. (a) MR behavior at 5 K for SFMO thin film grown at 800 1C. (b) Magnetic field dependence of magnetization at 5 K for SFMO thin film grown at 800 1C.
higher (12% at 8 T) as compared to the ( 3.80% MR at 8 T) polycrystalline thin film grown on STO polycrystalline substrate [16]. The typical coercive field obtained from MH and MR at 5 K is found to be 0.05 T and 0.55 T respectively. The observation of higher coercive field for MR curve is consistent with the result of Sarma et al. [21]. However, the two main mechanisms are responsible for magnetoresistance behavior in SFMO materials. The first is ascribed to grain boundaries and even impurity-phase grain boundaries, which lead to the inter-granular tunneling effect [1,11,20]. The second is intra-granular two-dimensional defects which are related to the intrinsic behavior, such as antisite disorder, antiphase boundaries and some domain boundaries [22]. However in our case, the polycrystalline film shows almost linear variation of MR at high field rather than its tendency to saturate. It is expected due to the intra-granular nature of grains, and also related with the antisite disordering between Fe and Mo ions. Since such disordering, [22], creates antiferromagnetic SrFeO3 regions in SFMO, one can expect antiferromagnetic ordering at the grain boundaries in SFMO films is contrast with the ferrimagnetic ordering in SFMO grains. Therefore, we purpose that the linear type MR behavior in our polycrystalline SFMO thin films could be observed due to the intrinsic property and antisite disordering
N. Kumar et al. / Materials Letters 118 (2014) 200–203
effect, which is defined as high field magnetoresistance (HFMR) type behavior as reported in bulk disordered samples [23]. 4. Conclusions The SFMO thin films were deposited at different temperatures ranging from 500 to 800 1C by pulsed laser deposition on STO buffered Si (100) substrates and the linear type MR behavior at 300 and 5 K was observed. The observation of room temperature magnetoresistance in SFMO thin films on Si (100) substrate is very promising and attractive for magnetoresistive and spintronic applications. Acknowledgment The authors acknowledge the financial support from DOE (grant DE-FG02-ER46526). One of the author N. Kumar gratefully acknowledges CSIR, India, for SRF fellowship to carry out this work as a part of his Ph.D. dissertation at NPL, New Delhi and NIT Kurukshetra, India. References [1] Kobayashi KI, Kimura T, Sawada H, Terakura K, Tokura Y. Nature 1998;395:677–80. [2] Sanchez D, Alonso JA, Garcia-Hernandez M, Martinez-Lope MJ, Martinez JL, Mellergard A. Phys Rev B 2002;65:104426–8.
203
[3] Tomioka Y, Okuda T, Okimoto Y, Kumai R, Kobayashi KI, Tokura Y. Phys Rev B 2000;61:422–7. [4] Huang YH, Yamauchi H, Karppinen M. Phys Rev B 2006;74:174418-6. [5] Poddar A, Bhowmik RN, Muthuselvam P, Das N. J Appl Phys 2009;106:0739088. [6] Suominen T, Raittila J, Paturi P. Thin Solid Films 2009;517:5793–7. [7] Paturi P, Metsanoja M, Huhtinen H. Thin Solid Films 2011;519:8047–52. [8] Santiso J, Figueras A, Fraxedas J. Surf Interface Anal 2002;33:676–80. [9] Jalili H, Heinig NF, Leung KT. J Appl Phys 2009;105:034305–6. [10] Kumar N, Misra P, Kotnala RK, Gaur A, Katiyar RS. J Phys D: Appl Phys Acceptance date 04 Dec 2013 (Article ID: D/483608/PAP). [11] Kumar N, Khurana G, Gaur A, Kotnala RK. J Appl Phys 2013;114:053902–5. [12] Bianchini L. Synthesizing and Characterizing Sr2FeMoO6 Bulk and Thin Films. Undergrad Rev 2008;4:65–70. [13] Wang S, Pan H, Zhang X, Lian G, Xion G. Appl Phys Lett 2006;88:121912–3. [14] Singh VN, Majumdar P. Europhys Lett 2011;94:47004–6. [15] Navarro J, Balcells LI, Sandiumenge F, Bibes M, Roig A, Martínez B, et al. J Phys: Condens Matter 2001;13:8481–8. [16] Shinde SR, Ogale SB, Greene RL, Venkatesan T, Tsoi K, Cheong SW, et al. J Appl Phys 2003;93:1605–12. [17] Muduli PK, Budhani RC, Topwal D, Sarma DD. Journal of Physics: Conference Series 2009;150:042132–4. [18] Saloaro M, Majumdar S, Huhtinen H, Paturi P. J Phys: Condens Matter 2012;24:366003–9. [19] Song JH, Park JH, Jeong YH. J Appl Phys 2005;97:046105-3. [20] Kumar N, Pandey V, Gaur A, Kotnala RK. J Appl Phys 2012;112:073925–6. [21] Sarma DD, Ray S, Tanaka K, Kobayashi M, Fujimori A, Sanyal P, et al. Phys Rev Lett 2007;98:157205-4. [22] Garcia-Hernandez M, Martinez JL, Martinez-Lope MJ, Casais MT, Alonso JA. Phys Rev Lett 2001;86:2443–6. [23] Sarma DD, Sampathkumaran EV, Ray S, Nagarajan R, Majumdar S, Kumar A, et al. Solid State Commun 2000;114:465–8.