Factors Determining the Permanent Magnet Properties of Single Crystals of Fe2NiAl

Abstract

It is shown that fine precipitated particles present in single crystals of Fe2NiAl are elongated and that the shape anisotropy of these particles is a major factor in determining the coercive force of Fe2NiAl. For fields of less than 7000 oersteds, 〈111〉 directions are the directions of easy magnetization in the (110) plane of the crystal; this is due to the effect of the shape of the precipitated particles, which are oriented in three mutually perpendicular directions. In higher fields, the torque due to this effect decreases and then the [001] direction is the direction of easy magnetization because of intrinsic crystal anisotropy. These conclusions are based on an analysis, and on measurements, of the torque on three mutually perpendicular rods of magnetic material. These rods simulate the preciptated particles in the actual crystal.