Introduction to Magnetism

Abstract

We begin our study of spin waves with a discussion of the origins of magnetism. A discussion on the dynamics of a spinning top, in Problem 1.1, helps us understand classical angular momentum. We then introduce the quantum mechanical concepts of angular momentum and Pauli spin operators in Problems 1.2–1.5. A discussion on the electronic structure of ions important to magnetism, their spectroscopic notation, and the use of Hund’s Rules to find the ground states of these ions is explained through Problems 1.6–1.7. Finally, in Problem 1.8, we estimate the magnetic moment per unit volume of the commonly used material, Yttrium Iron Garnet, based on the Fe$^{3+}$ ion.