1. Chapter 35 Magnetic Properties of Materials

2. E0E0 qq q E0E0 To describe this weakness of the electric field in an insulator, with “dielectric constant” k e : To describe this weakness of the electric field in an insulator, with “dielectric constant” k e : How dose magnetic field in the material?

3. The Magnetic Dipole Magnetic dipole     

4. Atomic and Nuclear Magnetism Orbital magnetic dipole moment Bohr magneton Orbital magnetic dipole moment Spin magnetic dipole moment

5. Magnetization unmagnetizedmagnetized

6. Magnetization unmagnetizedmagnetized magnetization M: There are three field: applied magnetic field B 0, magnetized field B M, net magnetic field B.

7. Magnetization unmagnetizedmagnetized surface current surface charge E’ BMBM

8. a long solenoid with a magnetic material

9. Electric FieldMagnitic Field Paramagnetism Diamagnetism

10. Magnetic Materials 1. Paramagnetism when B 0 /T is small The atoms of this material have permanent magnetic dipole moments. B 0 and μ 0 M are parallel, B > B 0. Curie’s Law B 0 increase M increase

11. 2. Diamagnetism B 0 and μ 0 M are antiparallel, B < B 0. motion mm mm mm Δμ m is antiparallel with B. μ m is parallel with B.  Δμ m >  μ m  Δμ m <  μ m ParamagnetismDiamagnetism

12. 3. Ferromagnetism κ m >>1, B >> B 0. 1. Paramagnetism B 0 and μ 0 M are parallel, B > B 0 κ m >1 2. Diamagnetism B 0 and μ 0 M are antiparallel, B < B 0 κ m <1 Magnetic domains B 0 =0B0B0 T>T C, Paramagnetism.

13. 3. Ferromagnetism κ m >>1, B >> B 0. 1. Paramagnetism 2. Diamagnetism B 0 and μ 0 M are parallel, B > B 0 κ m >1 B 0 and μ 0 M are antiparallel, B < B 0 κ m <1 Hysteresis Point c: remains magnetized even when the applied field B 0 is zero. Point e: retains a permanent magnetization. Ferromagnetism can “remember” how it became magnetized. T>T C, Paramagnetism.

14. Nuclear magnetism The nucleus has a magnetic moment with two parts: orbital magnetic moment of protons and intrinsic magnetic moment of protons and neutron. protons and neutrons Nuclear magnetic resonance

15. Electric FieldMagnetic Field

16. Electric FieldMagnetic Field

17. Electric FieldMagnetic Field Gauss Law Ampere Law

18. Magnetic Field Electric Field surface charge surface current

19. Magnetic Field Electric Field Electric polarization vector Electric displacement vector Magnetic field surface charge surface current

20. Electric FieldMagnetic Field Induction

21. Gauss’ Law for Magnetism The magnetic form of Gauss’law: The net flux of the magnetic field through any closed surface is zero.

22. Example

25. What is

26. L=0.5m, and 300 turn ， I=0.05A, what is B? A ferromagnetism cylinder is set, B=10T ， what is  r ； If there is no ferromagnetism cylinder, but B= 10T ， What is the current ？

27. Example Surface current Surface current density

28. Exercises P818-820 7, 11, 17, 31 Problems P820 3