Temperature and Magnetization Dependences of the Magneto-Crystalline Anisotropy Energy of Ni

Abstract

A model for the temperature and the magnetization dependences of the magneto-crystalline anisotropy energy for Ni has been proposed based on the itinerant electron model by considering the effect of thermally excited magnons on the spin-orbit interaction. The temperature variation of K₁ at low temperatures can be expressed by the terms proportional to T^3⁄2, T² and T^5⁄2. Experimentally determined values of the coefficient of the term T^3⁄2 is 586 erg/cm³deg^3⁄2, and other terms are found to be negligibly small. This small value of the term T² can be expected from the present model. Experimental values of the magnetization derivative of K₁ at a constant field are found to be much larger than those at a constant temperature, and this fact can also be explained by the present model.