Ferromagnetic Anisotropy of Nickel-Iron Crystals at Various Temperatures

Magnetization curves in important crystallographic directions at temperatures up to near the Curie points in small oblate spheroids cut from annealed face-centered cubic nickel-iron alloys with from 10 to 50 percent iron show a change in ferromagnetic anisotropy at about 24 percent iron. With less than this amount of iron the order of increasing difficulty for magnetization to saturation is, as in nickel at room temperature: 111>, 110>, 100>. With more than this amount of iron the order is 100>, 111>, 110>. A small decrease in the apparent demagnetizing factor of the spheroids with rising temperature was noted.