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研究Fe-N体系晶相转变(相变)规律对于高效合成高自旋极化率的γ'-Fe4N薄膜材料非常重要. 利用同步热分析(TG-DSC)研究了氮化铁薄膜的相变规律. TG-DSC的结果显示, 在10 ℃/min的升温速率下, γ''-FeN薄膜在常温到800 ℃之间共有5次相变, 分别为I, γ''-FeN→ξ-Fe2N; II, ξ-Fe2N→ε-Fe3N; III, ε-Fe3N→γ'-Fe4N; IV, γ'-Fe4N→γ-Fe; 以及V, γ-Fe→α-Fe. 利用真空退火技术有效调控了氮化铁薄膜的晶相. X-射线衍射测试结果显示, 直接在纯氮气中溅射得到的氮化铁薄膜是单相的γ''-FeN, 经350, 380和430 ℃退火可分别获得单相的ξ-Fe2N, ε-Fe3N和γ'-Fe4N. 研究了氮化铁薄膜的磁学性能. 振动样品磁强计测试结果显示, γ'-Fe4N薄膜在面内/面外表现出明显的磁各向异性, 属于典型的磁形状各向异性.The phase transition law of Fe-N system is very important for efficiently synthesizing single-phase γ'-Fe4N thin films. The γ"-FeN thin films are deposited on silicon wafers via DC reactive magnetron sputtering; some of them are stripped from the silicon wafers and measured by using the synchronous thermal analysis (TG-DSC) for studying the phase transition law of Fe-N system. The results of TG-DSC show that at a heating rate of 10 ℃/min, the Fe-N system has five phase transitions in a temperature range between room temperature (RT) and 800 ℃, i.e. I (330−415 ℃): γ''-FeN→ξ-Fe2N with an endothermic value of 133.8 J/g; II (415−490 ℃): ξ-Fe2N→ε-Fe3N with no obvious latent heat of phase change; III (510−562 ℃): ε-Fe3N→γ'-Fe4N with an exotherm value of 29.3 J/g; IV (590−636 ℃): γ'-Fe4N→γ-Fe with an exotherm value of 42.6 J/g; V (636−690 ℃): γ-Fe→α-Fe with an endothermic value of 14.4 J/g. According to the phase transition law of Fe-N system, the crystal phase of iron nitride thin film is effectively regulated by vacuum annealing. The x-ray diffraction pattern (XRD) results show that the iron nitride thin film obtained by direct-sputtering in pure N2 is a single-phase γ"-FeN film, and it becomes a single-phase ξ-Fe2N film after being annealed at 350 ℃ for 2 h, a single-phase ε-Fe3N film after being annealed at 380 ℃ for 2 h, and a single-phase γ'-Fe4N film after being annealed at 430 ℃ for 7 h. The annealing temperature for the phase transition of Fe-N thin film is generally lower than that predicted by the TG-DSC experimental results, because it is affected by the annealing time too, that is, prolonging the annealing time at a lower temperature is also effective for regulating the crystal phase of Fe-N thin film. The magnetic properties of the Fe-N thin film are also studied via vibrating sample magnetometer (VSM) at room temperature. The γ'-Fe4N polycrystalline thin film shows an easy-magnetized hysteresis loop for the isotropic in-plane one, but a hard-magnetized hysteresis loop with a large demagnetizing field for the out-of-plane one, which belongs to the typical magnetic shape anisotropy. However, their saturation magnetizations are really the same (about 950 emu/cm3) both in the plane and out of the plane.
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Keywords:
- semi-metal /
- crystal structure /
- simultaneous thermal analysis /
- magnetic anisotropy
[1] de Groot R A, Mueller F M, van Engen P G, et al. 1983 Phys. Rev. Lett. 50 2024Google Scholar
[2] 任尚坤, 张凤鸣, 都有为 2004 物理学进展 24 381Google Scholar
Ren S K, Zhang F M, Du Y W 2004 Prog. Phys. 24 381Google Scholar
[3] Strijkers G J, Ji Y, Yang F Y, et al. 2001 Phys. Rev. B 63 104510Google Scholar
[4] Vahidi M, Gifford J A, Zhang S K, et al. 2014 APL Mater. 2 046108Google Scholar
[5] Li S, Takahashi Y K, Sakuraba Y, et al. 2016 Appl. Phys. Lett. 108 122404Google Scholar
[6] Bosu S, Sakuraba Y, Sasaki T T, et al. 2016 Scripta Mater. 110 70Google Scholar
[7] Ramsteiner M, Brandt O, Flissikowski T, et al. 2008 Phys. Rev. B 78 121303Google Scholar
[8] Bruski P, Manzke Y, Farshchi R, et al. 2013 Appl. Phys. Lett. 103 052406Google Scholar
[9] 张炜, 千正男, 隋郁, 等 2005 物理学报 54 4879Google Scholar
Zhang W, Qian Z N, Sui Y, et al. 2005 Acta Phys. Sin. 54 4879Google Scholar
[10] 王本阳, 千正男, 隋郁, 等 2005 物理学报 54 3386Google Scholar
Wang B Y, Qian Z N, Sui Y, et al. 2005 Acta Phys. Sin. 54 3386Google Scholar
[11] Ji Y, Strijkers G J, Yang F Y, et al. 2001 Phys. Rev. Lett. 86 5585Google Scholar
[12] Ding Y, Yuan C, Wang Z, et al. 2014 Appl. Phys. Lett. 105 092401Google Scholar
[13] Wada E, Watanabe K, Shirahata Y, et al. 2010 Appl. Phys. Lett. 96 102510Google Scholar
[14] 唐晓莉, 张怀武, 苏桦, 等 2006 无机材料学报 21 741Google Scholar
Tang X L, Zhang H W, Su Y, et al. 2006 J. Inorg. Mater. 21 741Google Scholar
[15] Wang L L, Zheng W T, Gong J, et al. 2009 J. Alloy. Compd. 467 1Google Scholar
[16] Mi W B, Guob Z B, Fenga X P, et al. 2013 Acta Mater. 61 6387Google Scholar
[17] Kokado S, Fujima N, Harigaya K, et al. 2006 Phys. Rev. B 73 172410Google Scholar
[18] Wang X, Zheng W T, Tian H W, et al. 2003 Appl. Surf. Sci. 220 30Google Scholar
[19] Wang L L, Wang X, Ma N, et al. 2006 Surf. Coat. Tech. 201 786Google Scholar
[20] Wang L L, Wang X, Zheng W T, et al. 2006 Mater. Chem. Phys. 100 304Google Scholar
[21] Navío C, Alvarez J, Capitan M J, et al. 2009 Appl. Phys. Lett. 94 263112Google Scholar
[22] Zhang Q, Yang S A, Mi W, et al. 2016 Adv. Mater. 28 959Google Scholar
[23] Mi W B, Feng X P, Duan X F, et al. 2012 Thin Solid Films 520 7035Google Scholar
[24] Zhang Y, Mi W, Wang X, et al. 2015 Phys. Chem. Chem. Phys. 17 15435Google Scholar
[25] Mi W B, Feng X P, Bai H L 2011 J. Magn. Magn. Mater. 323 1909Google Scholar
[26] 米文博, 王晓姹 2015 高自旋极化磁性材料(天津: 天津大学出版社) 第124页
Mi W B, Wang X C 2015 High Spin Polarized Magnetic Materials (Tianjin: Tianjin University Press) p124 (in Chinese)
[27] Widenmeyer M, Niewa R, Hansen T C, et al. 2013 Z. Anorg. Allg. Chem. 639 285Google Scholar
[28] Widenmeyer M, Hansen T C, Meissner E, et al. 2014 Z. Anorg. Allg. Chem. 640 1265Google Scholar
[29] Lu Q, Xie M, Han G, et al. 2019 J. Magn. Magn. Mater. 474 76Google Scholar
[30] Mohn P, Matar S F 1999 J. Magn. Magn. Mater. 191 234Google Scholar
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表 1 TG-DSC曲线关键节点处Fe-N的化学组分、主要晶相和晶型
Table 1. Chemical composition, main crystal phase, and crystal form of the Fe-N at key nodes of the TG-DSC curve.
温度/℃ 化学组分 主要晶相 晶型 330 FeN1.1 γ''-FeN 立方 415 Fe2N1.3 ξ-Fe2N 六角 490 Fe3N1.4 ε-Fe3N 六角 510 Fe3N1.3 ε-Fe3N 六角 562 Fe4N γ'-Fe4N 立方 (Fe构成面心立方, N位于体心) 590 Fe4N0.7 γ'-Fe4N 立方 636 Fe4N0.37 γ-Fe 面心立方 690 Fe α-Fe 体心立方 -
[1] de Groot R A, Mueller F M, van Engen P G, et al. 1983 Phys. Rev. Lett. 50 2024Google Scholar
[2] 任尚坤, 张凤鸣, 都有为 2004 物理学进展 24 381Google Scholar
Ren S K, Zhang F M, Du Y W 2004 Prog. Phys. 24 381Google Scholar
[3] Strijkers G J, Ji Y, Yang F Y, et al. 2001 Phys. Rev. B 63 104510Google Scholar
[4] Vahidi M, Gifford J A, Zhang S K, et al. 2014 APL Mater. 2 046108Google Scholar
[5] Li S, Takahashi Y K, Sakuraba Y, et al. 2016 Appl. Phys. Lett. 108 122404Google Scholar
[6] Bosu S, Sakuraba Y, Sasaki T T, et al. 2016 Scripta Mater. 110 70Google Scholar
[7] Ramsteiner M, Brandt O, Flissikowski T, et al. 2008 Phys. Rev. B 78 121303Google Scholar
[8] Bruski P, Manzke Y, Farshchi R, et al. 2013 Appl. Phys. Lett. 103 052406Google Scholar
[9] 张炜, 千正男, 隋郁, 等 2005 物理学报 54 4879Google Scholar
Zhang W, Qian Z N, Sui Y, et al. 2005 Acta Phys. Sin. 54 4879Google Scholar
[10] 王本阳, 千正男, 隋郁, 等 2005 物理学报 54 3386Google Scholar
Wang B Y, Qian Z N, Sui Y, et al. 2005 Acta Phys. Sin. 54 3386Google Scholar
[11] Ji Y, Strijkers G J, Yang F Y, et al. 2001 Phys. Rev. Lett. 86 5585Google Scholar
[12] Ding Y, Yuan C, Wang Z, et al. 2014 Appl. Phys. Lett. 105 092401Google Scholar
[13] Wada E, Watanabe K, Shirahata Y, et al. 2010 Appl. Phys. Lett. 96 102510Google Scholar
[14] 唐晓莉, 张怀武, 苏桦, 等 2006 无机材料学报 21 741Google Scholar
Tang X L, Zhang H W, Su Y, et al. 2006 J. Inorg. Mater. 21 741Google Scholar
[15] Wang L L, Zheng W T, Gong J, et al. 2009 J. Alloy. Compd. 467 1Google Scholar
[16] Mi W B, Guob Z B, Fenga X P, et al. 2013 Acta Mater. 61 6387Google Scholar
[17] Kokado S, Fujima N, Harigaya K, et al. 2006 Phys. Rev. B 73 172410Google Scholar
[18] Wang X, Zheng W T, Tian H W, et al. 2003 Appl. Surf. Sci. 220 30Google Scholar
[19] Wang L L, Wang X, Ma N, et al. 2006 Surf. Coat. Tech. 201 786Google Scholar
[20] Wang L L, Wang X, Zheng W T, et al. 2006 Mater. Chem. Phys. 100 304Google Scholar
[21] Navío C, Alvarez J, Capitan M J, et al. 2009 Appl. Phys. Lett. 94 263112Google Scholar
[22] Zhang Q, Yang S A, Mi W, et al. 2016 Adv. Mater. 28 959Google Scholar
[23] Mi W B, Feng X P, Duan X F, et al. 2012 Thin Solid Films 520 7035Google Scholar
[24] Zhang Y, Mi W, Wang X, et al. 2015 Phys. Chem. Chem. Phys. 17 15435Google Scholar
[25] Mi W B, Feng X P, Bai H L 2011 J. Magn. Magn. Mater. 323 1909Google Scholar
[26] 米文博, 王晓姹 2015 高自旋极化磁性材料(天津: 天津大学出版社) 第124页
Mi W B, Wang X C 2015 High Spin Polarized Magnetic Materials (Tianjin: Tianjin University Press) p124 (in Chinese)
[27] Widenmeyer M, Niewa R, Hansen T C, et al. 2013 Z. Anorg. Allg. Chem. 639 285Google Scholar
[28] Widenmeyer M, Hansen T C, Meissner E, et al. 2014 Z. Anorg. Allg. Chem. 640 1265Google Scholar
[29] Lu Q, Xie M, Han G, et al. 2019 J. Magn. Magn. Mater. 474 76Google Scholar
[30] Mohn P, Matar S F 1999 J. Magn. Magn. Mater. 191 234Google Scholar
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