Magnetic Properties of Solids

Magnetic Susceptibilities of Paramagnetic and Diamagnetic Materials at 20°C

20°C时铁磁性与抗磁性材料的磁化率

Material 材料	χ_m=K_m-1 (x 10^-5)
Paramagnetic 顺磁的
Iron oxide (FeO) 氧化铁（FeO）	720
Iron amonium alum 铁铵明矾	66
Uranium 铀	40
Platinum 铂	26
Tungsten 钨	6.8
Cesium 铯	5.1
Aluminum 铝	2.2
Lithium 锂	1.4
Magnesium 镁	1.2
Sodium 钠	0.72
Oxygen gas 氧气	0.19
Diamagnetic 顺磁性
Ammonia 氨	-.26
Bismuth 铋	-16.6
Mercury 水星	-2.9
Silver 银	-2.6
Carbon (diamond) 碳（钻石）	-2.1
Carbon (graphite) 碳（石墨）	-1.6
Lead 铅	-1.8
Sodium chloride 氯化钠	-1.4
Copper 铜	-1.0
Water 水	-0.91

Paramagnetism

顺磁性

Diamagnetism

顺磁性

Here the quantity K_m is called the relative permeability, a quantity which measures the ratio of the internal magnetization to the applied magnetic field. If the material does not respond to the magnetic field by magnetizing, then the field in the material will be just the applied field and the relative permeability K_m =1. A positive relative permeability greater than 1 implies that the material magnetizes in response to the applied magnetic field. The quantity χ_m is called magnetic susceptibility, and it is just the permeability minus 1. The magnetic susceptibility is then zero if the material does not respond with any magnetization. So both quantities give the same information, and both are dimensionless quantities.

For ordinary solids and liquids at room temperature, the relative permeability K_m is typically in the range 1.00001 to 1.003. We recognize this weak magnetic character of common materials by the saying "they are not magnetic", which recognizes their great contrast to the magnetic response of ferromagnetic materials. More precisely, they are either paramagnetic or diamagnetic, but that represents a very small magnetic response compared to ferromagnets.

对于常温下的普通固体和液体，相对磁渗透率Km通常在1.00001到1.003之间。我们通过‘它们不磁性’的说法来认识普通材料的弱磁性，这与铁磁材料的磁响应形成鲜明对比。更准确地说，它们要么是顺磁的，要么是抗磁的，但这种磁响应远小于铁磁材料的磁响应。

The gases N₂ and H₂ are weakly diamagnetic with susceptabilities -0.0005 x 10^-5 for N₂ and -0.00021 x 10^-5 for H₂. That is in contrast to the large paramagnetic susceptability of O₂ in the table.

N₂和H₂是弱磁性的，其磁化率分别为-0.0005×10⁻⁵（对于N₂）和-0.00021×10⁻⁵（对于H₂）。这与表中O₂的较大顺磁性磁化率形成对比。

这里的量 K_m 被称为相对磁导率，这是一个衡量内部磁化强度与施加磁场比值的量。如果材料不对磁场产生磁化，则材料中的磁场将只是施加的磁场，此时相对磁导率 K_m = 1。正的相对磁导率大于 1 表示材料会对施加的磁场产生磁化。量 χ_m 被称为磁化率，它就是磁导率减 1。因此，磁化率为零表示材料不对磁场产生任何磁化。因此，两个量提供相同的信息，且都是无量纲量。

Magnetic Properties of Ferromagnetic Materials

铁磁性材料的磁性特性

Material 材料	Treatment 处理	Initial Relative Permeability 初始相对渗透性	Maximum Relative Permeability 最大相对磁导率	Coercive Force (oersteds) 矫力（奥斯特）	Remanent Flux Density (gauss) 剩余磁感应强度（高斯）
Iron, 99.8% pure 铁，纯度为99.8%	Annealed 退火	150	5000	1.0	13,000
Iron, 99.95% pure 铁，纯度为99.95%	Annealed in hydrogen 在氢中退火	10,000	200,000	0.05	13,000
78 Permalloy 78 铁氧体	Annealed, quenched 退火，淬火	8,000	100,000	.05	7,000
Superpermalloy 超permalloy	Annealed in hydrogen, controlled cooling 在氢中退火，受控冷却	100,000	1,000,000	0.002	7,000
Cobalt, 99% pure 钴，纯度99%	Annealed 退火	70	250	10	5,000
Nickel, 99% pure 镍，纯度为99%	Annealed 退火	110	600	0.7	4,000
Steel, 0.9% C 钢，含碳量0.9%	Quenched 淬火	50	100	70	10,300
Steel, 30% Co 钢，30%钴	Quenched 淬火	...	...	240	9,500
Alnico 5 铝镍钴5号	Cooled in magnetic field 在磁场中冷却	4	...	575	12,500
Silmanal Silmanal（专名或术语）	Baked 烘烤的	...	...	6,000	550
Iron, fine powder 铁粉	Pressed 压紧的	...	...	470	6,000

In this table the remanent flux density is the retained magnetic field B, and the SI unit for B is the Tesla (T). 1 Tesla = 10,000 gauss. The "coercive force" is the applied reverse magnetic field strength H required to force the net magnetic field back to zero after magnetization. The SI unit for H is A/m, and 1 A/m = 0.01257 oersteds.

在本表中，剩余磁感应强度是保留的磁场B，B的SI单位是特斯拉（T）。1特斯拉=10,000高斯。‘矫顽力’是使磁化后的净磁场恢复到零所需的反向磁场强度H。H的SI单位是A/m，1A/m=0.01257奥斯特。