Surface of Magnetization, Field, and Temperature for Nickel near Its Curie Temperature

J. E. Noakes and A. Arrott

 

• Scientific Laboratory, Ford Motor Company, Dearborn, Michigan

Abstract

 

A nickel single‐crystal sphere is placed in a solenoid with a 100 axis along the solenoid axis. The solenoid is placed in an electromagnet with the field at right angles to the solenoid axis and along another 100 axis of the nickel crystal. A detector coil is placed with its axis parallel to the solenoid in order to measure the change in the component of the magnetization of the sphere along the solenoid when the 20‐G field in the solenoid is reversed. This component is measured as a function of the transverse field of the electromagnet to obtain the effective susceptibility in applied fields from 20 to 5000 G. A sufficient time is allowed between each change of the electromagnet field for the large magnetocaloric effects to decay and the sample to return to the furnace temperature. The temperature dependence of the spontaneous magnetization in zero internal field and of the initial rate of increase with field of magnetization above the spontaneous magnetization below the Curie temperature, the temperature dependence of the initial susceptibility above the Curie temperature, and the field dependence of the magnetization at the Curie temperature and at a number of nearby temperatures are obtained. The single‐crystal results show sharper indications of the spontaneous magnetization than do identical measurements on polycrystalline Ni. The difference is attributed to Dzialoshinski interactions at grain boundaries. Analytic representations of some of the data are given.

 

https://sci-hub.tw/https://aip.scitation.org/doi/abs/10.1063/1.1709707