Determination of Magnetic Anisotropy Constants from Unsaturated Torque Curves in Nd₂Fe₁₄B

Abstract

A simple method has been established for a determination of the magnetic anisotropy constants from an unsaturated torque curve. In this method a least mean square routine was adopted instead of the usual Fourier analysis which has been widely used by many authors. The method has been applied to the recently developed high energy permanent magnet, Nd₂Fe₁₄B, of which torque curves were not saturated by using an ordinary electromagnet. The validity of the present method has been checked by applying it to the case of hcp Co for which the saturated values were known.