Edward C. Jordan Memorial Offering of the First Course under the Indo-US Inter-University Collaborative Initiative in Higher Education and Research: Electromagnetics for Electrical and Computer Engineering by Nannapaneni Narayana Rao Edward C. Jordan Professor of Electrical and Computer Engineering University of Illinois at Urbana-Champaign Urbana, Illinois, USA Amrita Viswa Vidya Peetham, Coimbatore July 10 – August 11, 2006

4.3 Magnetic Materials

Magnetic Materials Diamagnetism: are based upon the property of magnetization, which is the phenomenon of creation of magnetic dipoles within the material. Diamagnetism: A net dipole moment is induced by changing the angular velocities of the electronic orbits. Dipole moment m = IA an

Paramagnetism Already existing dipoles are acted upon by a torque.

The phenomenon of magnetization results in a magnetization current in the material which produces a secondary B.

Magnetization Current

To take into account the effect of magnetization, we define the magnetic field intensity vector, H, as mr and m vary with the material, implicitly taking into account the effect of magnetization.

As an example, consider Then inside the material,

D4.6 For 0 < z < d, (a)

(b) (c)