Is the magnetic anisotropy proportional to the orbital moment?

Authors

Ralph Skomski, University of Nebraska-LincolnFollow
Arti Kashyap, University of Nebraska-LincolnFollow
Axel Enders, University of Nebraska–LincolnFollow

Date of this Version

2011

Citation

JOURNAL OF APPLIED PHYSICS 109, 07E143 (2011); doi:10.1063/1.3562445

Comments

Copyright 2011 American Institute of Physics

Abstract

The relation between orbital moment and magnetic anisotropy is investigated by model calculations, which show that only a part of the spin-orbit coupling contributes to the anisotropy. A large part of the anisotropy energy, about 50% for iron series elements and nearly 100% for rare-earths, is stored in the nonrelativistic part of the Hamiltonian. A feature important for x-ray magnetic circular dichroism is that the orbital moment of heavy atoms rotates with the spin moment, whereas in light atoms, the orbital moment is recreated in each different direction. In the discussion, we consider three examples of current interest in different areas of magnetism, namely, spin-orbit coupling in Gd³⁺ and Eu²⁺, surface anisotropy of Nd₂Fe₁₄B, and multiferroic magnetization switching using rare-earths.