Ferromagnetic Anisotropy of Iron Crystals at Various Temperatures

Abstract

Magnetization curves in important crystallographic directions in small oblate spheroids cut from hydrogen-purified iron crystals show ferromagnetic anisotropy of the same sort as that previously reported for iron of less purity. At room temperature agreement with earlier work is good. At 296°C and at 500°C the principal (fourth-order) term in the anisotropy is larger, at 650°C and 696°C the same term is smaller than in earlier studies, anisotropy not being detected. The subsidiary (sixth-order) term is not accurately determined. The pendulum magnetometer method, which has certain advantages for such purposes over classical methods, was used and results for different spheroids agree well, especially at the higher temperatures.