矫顽力

矫顽力（coercivity）也称为矫顽性或保磁力，是磁性材料的特性之一，是指在磁性材料已经磁化到磁饱和后，要使其磁化强度减到零所需要的磁场强度。矫顽力代表磁性材料抵抗退磁的能力，会用H_C的符号表示，单位为A/m（国际标准制）或Oe（高斯单位制）。矫顽力可以用磁强计或是B-H分析仪量测。

若铁磁性材料（包含亚铁磁性材料）的矫顽力大，则称为硬磁性，可以用来作为永久磁铁的材料。永久磁铁可以用在马达、磁性储存媒体（如硬盘、磁盘片或磁带）、及矿石处理中的磁性分离器。

矫顽力小的铁磁性材料则称为软磁性，可以用在变压器及电感器的铁芯，磁性储存媒体的读写头（英语：recording head）、微波设备及电磁屏蔽设备中。

磁性材料的矫顽力一般是用量测磁滞曲线（也称为磁化曲线）来求得。采集数据的仪器一般会用振动样品磁强计（英语：vibrating sample magnetometer）或是交变梯度磁强计，当量测到的磁通密度数据为零时，对应的磁场强度即为矫顽力。若様品中含有铁磁性材料，在磁场增加及减少时，所量测到的矫顽力会不同，这是因为交换偏置场（英语：exchange bias）效应的结果。

材料量测到的矫顽力也和量测磁化曲线过程花的时间有关。一磁体材料在一反向磁场中量到的磁化强度会小于矫顽力，而且若长期在相同条件下量测，其值会驰豫（relaxation）至零。驰豫现象是因为磁畴在反向磁场下因热产生的效应，而且受磁粘滞系数（magnetic viscosity）的影响^[1]。有些材料的矫顽力会随频率而增加，这是高带宽（英语：bandwidth (computing)）磁性储存设备要提高资料速度的一大障碍，因为要增加储存密度也就意味着储存设备要有更高的矫顽力^{[来源请求]}。

更多信息 材料, 矫顽力 [Oe (A/m)] ...

软铁磁性材料及硬铁磁性材料的矫顽力
铁磁性材料的“硬度”随着晶体变大而增加
随着平滑程度及玻璃质程度增加而减少
材料	矫顽力 [Oe (A/m)]
[.1Mn:]6Fe:27Ni:Mo, 超导磁率合金	0.002^[2] (0.16)
Fe:4Ni, 透磁合金	0.01^[3]–1^[4] (0.8-80)
.9995 铁	0.05^[2]–470^[5] (4-37,000)
11Fe:Si，硅钢	0.4–0.9^[6] (32-72)
熟铁 (1896)	2^[7] (160)
.99 镍	0.7^[5]–290^[8] (56-23,000)
Zn_xFeNi_1-xO₃, 多腔磁控管中用的铁氧体	15–200^[9] (1200-16,000)
2Fe:Co^[10], 磁铁杆	240^[5] (19,000)
>.99 钴	10-900^[11] (800-72,000)
6Al:18Fe:8Co:Cu:6Ni– 3Ti:8Al:20Fe:20Co:2Cu:8Ni, alnico 5–9，冰箱磁铁或更强力的磁铁	640^[12]–2000^[13] (51,000-1.6*10⁵)
Cr:Co:Pt, 硬盘的储存媒介	1700^[14] (1.4*10⁵)
2Nd:14Fe:B，钕铁硼磁铁	10,000^[15]–12,000^[16] ((8-9.5)*10⁵)
12Fe:13Pt, Fe₄₈Pt₅₂	12,300+^[17] (9.8*10⁵)
?(Dy,Nb,Ga,Co):2Nd:14Fe:B	25,600^[18]/–26,300^[19] (2*10⁶)
2Sm:17Fe:3N，钐-铁-氮（10 K）	<500^[20]–35,000^[21] (40,000-2.8*10⁶)
Sm:5Co，钐钴磁铁	40,000^[22] (3.2*10⁶)

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若一有矫顽力的铁磁性材料放在外加磁场中，磁化强度延著外加磁场方向的分量为零。有二种磁化反转的方式：单域（英语：single domain (magnetic)）旋转及磁畴壁（英语：Domain wall (magnetism)）运动。当材料的磁化强度因单域旋转而反向时，磁化强度延著外加磁场方向的分量为零，磁化强度会垂直外加磁场。当材料的磁化强度因磁畴壁运动而反向时，所有小磁畴的磁化强度总和接近零，总磁化强度非常小。在一些基础研究中用到，较理想的磁性材料，其磁化强度主要是由单域旋转及磁晶各向异性（英语：magnetocrystalline anisotropy）所影响^[23]。在实际工程使用的磁性材料中，杂质及晶界是反向磁化磁域的成核来源，此时磁化强度反向主要由磁畴壁运动来控制。不过磁畴壁运动在矫顽力中的影响相当复杂，因此晶体缺陷可能是成核来源，但也可能固定住磁畴壁。磁畴壁在铁磁性材料中角色类似晶界在塑性变形中的角色，因为磁畴壁和晶界都属于晶体缺陷中的面缺陷。

若是材料有磁滞现象且已被磁化，在磁化曲线内的面积即为对材料施加反向外加磁场，使材料有反向磁化强度所需要的功，此能量最后会以热能的形式散失。磁性材料中常见的耗散过程包括磁致伸缩及磁畴壁的运动。矫顽力可以用来度量磁滞程度的多寡，也可以作为软铁磁性材料一般应用中损失的一个指标。

磁性材料的方形度（squareness）是剩磁除以矫顽力的商，硬铁磁性材料的方形度及矫顽力二者是硬铁磁性材料的二个重要性能指标，不过二者的乘积磁能积则更常提及。

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[15]
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[18]
G. Bai; R.W. Gao, Y. Sun, G.B. Han, B. Wang. Study of high-coercivity sintered NdFeB magnets. Journal of Magnetism and Magnetic Materials. 2006-05-24, 308 (1). doi:10.1016/j.jmmm.2006.04.029.
[19]
H. Jianga,; J. Evansa, M.J. O’Sheaa, Jianhua Dub. Hard magnetic properties of rapidly annealed NdFeB thin films on Nb and V buffer layers. Journal of Magnetism and Magnetic Materials. 2001-04-11, 224 (3). doi:10.1016/S0304-8853(01)00017-8.
[20]
Nakamura, Hajm; Kurihara, K.; Tatsuki, T.; Sugimoto, Satoshi; Okada, Masuo; Homma, Motofumi. Phase Changes and Magnetic Properties of Sm₂Fe₁₇N_x Alloys Heat-Treated in Hydrogen. IEEE Translation Journal on Magnetics in Japan. 1992, 7 (10). doi:10.1109/TJMJ.1992.4565502.
[21]
RANI R.; HEGDE H. ; NAVARATHNA A. ; CADIEU F. J. High coercivity Sm₂Fe₁₇N_x and related phases in sputtered film samples. Journal of applied physics. 1993, 73 (10) [2013-03-22]. （原始内容存档于2012-06-12）.
[22]
M. F. de Campos1; F. J. G. Landgraf, N. H. Saito, S. A. Romero, A. C. Neiva, F. P. Missell, E. de Morais, S. Gama, E. V. Obrucheva, and B. V. Jalnin. Chemical composition and coercivity of SmCo₅ magnets. Journal of Applied Physics. 1998, 84 (1). doi:10.1063/1.368075.
[23]
Genish, Isaschar; Kats, Yevgeny; Klein, Lior; Reiner, James W.; Beasley, M. R. Local measurements of magnetization reversal in thin films of Sr Rb O₃. physica status solidi (c). 2004, 1 (12): 3440–3442. doi:10.1002/pssc.200405476.

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Magnetization reversal applet (coherent rotation)
有关各种磁性记录材料的矫顽力列表，请参考fujifilmusa.com中的"Degaussing Data Storage Tape Magnetic Media" (PDF)

[Gaunt_1996-1] [1]
Gaunt, P. Magnetic viscosity and thermal activation energy. Journal of Applied Physics. 1986, 59 (12): 4129–4132. Bibcode:1986JAP....59.4129G. doi:10.1063/1.336671.

[Magn-2] [2]
Iron and Magnetism. 2003-12-06 [2013-03-15]. （原始内容存档于2008-02-04）（英语）.

[upd-3] [3]
Hojun Lee, Wonbae Bang, Kimin Hong, Young-Dong Ko, Jinseok Chung, Keeju Jeong and Heebok Lee. Magnetism and magneto impedance of% electroplated Ni-Fe permalloy thin films (PDF). [2013-03-23]. （原始内容 (PDF)存档于2012-02-15）.

[doi_1_365100-4] [4]
M. A. Akhter; D. J. Mapps, Y. Q. Ma Tan, Amanda Petford-Long, and R. Doole. Thickness and grain-size dependence of the coercivity in permalloy thin films. Journal of Applied Physics. 1997, 81 (8). doi:10.1063/1.365100.

[magprop-5] [5]
Magnetic Susceptibilities of Paramagnetic and Diamagnetic Materials at 20°C. Georgia State University, hyperphysics. [2013-03-23]. （原始内容存档于2014-08-22）.

[cartech-6] [6]
cartech.ides.com^{[失效链接]}

[Dynamo-7] [7]
Silvanus Phillips Thompson. Dynamo-electric machinery. 美国: 哈佛大学. 1896: 133 [2013-03-22]. （原始内容存档于2020-05-08）.

[Influence-8] [8]
M. S. Miller; F. E. Stageberg, Y. M. Chow, K. Rook, and L. A. Heuer. Influence of rf magnetron sputtering conditions on the magnetic, crystalline, and electrical properties of thin nickel films. Journal of Applied Physics. 1994, 75 (10). doi:10.1063/1.355560.

[NiZn-9] [9]
Wang, Geng; Sivertsen, John M.; Judy, Jack H. NiZn ferrite thin films prepared by Facing Target Sputtering. IEEE Transactions on Magnetics. 2011-09-27, 33 (5): 3748 – 3750. doi:10.1109/20.619559. |year=与|date=不匹配 (帮助);

[optics-10] [10]
Jon Orloff. Handbook of Charged Particle Optics, Second Edition. Taylor & Francis. 2008: 142 [2013-03-22]. ISBN 1420045555. （原始内容存档于2020-09-24）.

[jp045554t-11] [11]
doi/abs/10.1021/jp045554t. [2013-03-05]. （原始内容存档于2015-10-18）.

[dextermag-12] [12]
Alnico Magnets (PDF). Dexter. [2013-03-23].^{[永久失效链接]}

[ieee1066731-13] [13]
ieee article number=1066731 互联网档案馆的存档，存档日期2009-08-20.

[CoPtCr-14] [14]
Yang, Ming M. Laminated CoPtCr/Cr films for low noise longitudinal recording. IEEE Transactions on Magnetics. 2011-09-27, 27 (6): 5052 – 5054. doi:10.1109/20.278737. |year=与|date=不匹配 (帮助);

[NdFeB-15] [15]
C. D. Fuerst; E. G. Brewer. High‐remanence rapidly solidified Nd‐Fe‐B: Die‐upset magnets (invited). Journal of Applied Physics. 1993, 73 (10). doi:10.1063/1.353563.

[wondermagnet-16] [16]
Magnet and Magnetism FAQ. wondermagnet. [2013-03-23].

[chen_Nikles_2002-17] [17]
Chen, Min; Nikles, David E. Synthesis, self-assembly, and magnetic properties of Fe_x Co_y Pt_100-x-y nanoparticles. Nano Letters. 2002, 2 (3): 211–214. doi:10.1021/nl015649w.

[sinter-18] [18]
G. Bai; R.W. Gao, Y. Sun, G.B. Han, B. Wang. Study of high-coercivity sintered NdFeB magnets. Journal of Magnetism and Magnetic Materials. 2006-05-24, 308 (1). doi:10.1016/j.jmmm.2006.04.029.

[MMM-19] [19]
H. Jianga,; J. Evansa, M.J. O’Sheaa, Jianhua Dub. Hard magnetic properties of rapidly annealed NdFeB thin films on Nb and V buffer layers. Journal of Magnetism and Magnetic Materials. 2001-04-11, 224 (3). doi:10.1016/S0304-8853(01)00017-8.

[Sm2Fe17Nx-20] [20]
Nakamura, Hajm; Kurihara, K.; Tatsuki, T.; Sugimoto, Satoshi; Okada, Masuo; Homma, Motofumi. Phase Changes and Magnetic Properties of Sm₂Fe₁₇N_x Alloys Heat-Treated in Hydrogen. IEEE Translation Journal on Magnetics in Japan. 1992, 7 (10). doi:10.1109/TJMJ.1992.4565502.

[inist-21] [21]
RANI R.; HEGDE H. ; NAVARATHNA A. ; CADIEU F. J. High coercivity Sm₂Fe₁₇N_x and related phases in sputtered film samples. Journal of applied physics. 1993, 73 (10) [2013-03-22]. （原始内容存档于2012-06-12）.

[SmCo5-22] [22]
M. F. de Campos1; F. J. G. Landgraf, N. H. Saito, S. A. Romero, A. C. Neiva, F. P. Missell, E. de Morais, S. Gama, E. V. Obrucheva, and B. V. Jalnin. Chemical composition and coercivity of SmCo₅ magnets. Journal of Applied Physics. 1998, 84 (1). doi:10.1063/1.368075.

[Genish-23] [23]
Genish, Isaschar; Kats, Yevgeny; Klein, Lior; Reiner, James W.; Beasley, M. R. Local measurements of magnetization reversal in thin films of Sr Rb O₃. physica status solidi (c). 2004, 1 (12): 3440–3442. doi:10.1002/pssc.200405476.

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矫顽力

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矫顽力

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