1. Classifications of magnetic materials
Diamagnets  =-10-5
ex) Cu, silver, gold bismuth, beryllium,
superconductor (=-1)
Paramagnets  =10-3 ~10-5
 The magnetization of paramagnets is weak but aligned parallel with direction of the magnetic field
ex) Al, Platinum, Mn
3. Ferromagnets  >1 (cf.  50 to 10000)
ex) Fe, Co, Ni, Sm, Dy, Tb

2. 자기감수율(magnetic susceptibility) & 상대투자율(relative permeability)
Bm:물질 내부유도 자기장

3. Values of    for various materials
   constant in dia, paramagets
   are strongly affected by H  T in ferro
Dia, para, ferro
Other materials are all very closely related to ferromagnets because they are magnetically ordered
ex) ferrimmgnets, antiferromagnets,
helimagnets  superparamagnets

4. Magnetic Properties of Ferromagets
Ferromagnetism-Basic Properties
Spontaneous magnetization Ms(T) below Tc
T   Ms(T)  : T  TC  MS (T)  0
Magnetic properties reproducible on heating above TC, provided no structural change during heating
No macroscopically observable apparent (net) magnetization at zero field
Net magnetization by applied magnetic field

6. Ferromagnetism-Domains
Spontaneously magnetized regions separated by domain walls
180º domain walls: 90º domain walls
Domain size determination by energy balance between magnetostatic energy and domain wall energy 

7. Ferromagnetism-Hysteresis Loops
Magnetization process: domain wall motion and spin rotation
Remanent magnetization, remanence ratio, coercive force coercivity)
Coercivity(strongly structure-sensitive)
varies)