The Magnetocrystalline Anisotropy of Gadolinium

Abstract

Measurements of the magnetocrystalline anisotropy constants have been made on a single crystal of gadolinium using a torque magnetometer. The apparatus used is briefly described and the application of corrections for lack of saturation and for a paramagnetic component are explained. Measurements have been made between 37.5 °K and 315 °K and it is found that three constants are required to represent the results. It is shown that at temperatures greater than 240 °K the easy direction is the hexagonal axis. Below this temperature the easy direction lies on a cone whose axis is the c axis, and the variation of cone angle with temperature is calculated from the values of the anisotropy constants.