2. Classification of Magnetic media磁介质的分类 Based on the relation between B and b, the matter can be divided into three kinds: →(1) Paramagnetic substance(顺磁质):B'has same direction of B, that is B>b; (2) Diamagnetic substance(抗磁质):Bis matter opposite to Bo, that is B<Bo; 3) Ferromagnetic substance(铁磁质):Bhas the same direction of b. and B>>b
2.Classification of Magnetic Media 磁介质的分类 Based on the relation between and , the matter can be divided into three kinds: B B matter (1)Paramagnetic substance(顺磁质 ): has same direction of , that is ; B B B B (2) Diamagnetic substance(抗磁质）： is opposite to , that is ; B B0 B B0 (3)Ferromagnetic substance(铁磁质): has the same direction of and ; B B0 B B
3. Permeability(磁导率) Take the long solenoid(长直螺线管) as an example: (●● 0 .Ooooooo.o°10o° P B 888X88888888⑧8888888888 The ratio of B and Bo is called the relative permeability of the material and represented by u B
3. Permeability（磁导率） • P B0 0 I • P B 0 I Take the long solenoid(长直螺线管） as an example: The ratio of B and B0 is called the relative permeability of the material and represented by : r = B B r
oooooooooooo10° PB B 8888888888888888888∞8888888888888888 B0=10n B=u Bo=bou nl=anl Here u is defined as the permea bility of material. For the three kinds of magnetic substances, we have or vacuun 真空 0J0 r paramagnetic subs tance顺磁质 for diamagnetic subs tance抗磁质 Ao for ferromagnetic subs tance铁磁质
B nI 0 = 0 Here is defined as the permeability of material. For the three kinds of magnetic substances, we have = for ferromagnetic substance for diamagnetic substance for paramagneti c substance for vacuum 0 0 0 0 真空 顺磁质 抗磁质 铁磁质 • P B0 0 I • P B 0 I B B nI nI = r = r =
or I for vacuum 真空 matter s1 or paramagnetic subs tance顺磁质 < I for diamagnetic subs tance抗磁质 (1 for ferromagnetic subs tance铁磁质
= for ferromagne tic substance for diamagneti c substance for paramagneti c substance for vacuum r or 真空 顺磁质 抗磁质 铁磁质 matter
s 11-2 Molecular Theory of Paramagnetism Diamagnetism 顺磁质和抗磁质磁化的分子理论 1. The basic theory: ■日■口口口冒■■■■ ● Molecule 命 electron atom Charged and spin
§ 11-2 Molecular Theory of Paramagnetism & Diamagnetism 顺磁质和抗磁质磁化的分子理论 1. The basic theory: atom Molecule electron Charged and spin