The spontaneous magnetization of nickel + copper alloys

The spontaneous magnetization (σ0, T) of a ferromagnetic may be deduced exclusively from the determination of magnetic isothermals, or in conjunction with magnetocaloric measurements. Values of σ0, T of a nickel + copper alloy containing 30·75 at. % of copper have been obtained near its Curie temperature using both of these techniques and are shown to be in good agreement. Measurements of spontaneous magnetization and Curie temperature (θf) of nickel + copper alloys containing up to 54·11 at. % of copper using the purely magnetic techniques are described. These measurements were performed over a temperature range from θf down to 80 °K in all cases, and to 23 °K in the cases of alloys containing over 30 at. % of copper. The magnetic moments per atom (pB) of the alloys, which are deduced from the measurements, vary linearly over a wide range of composition, extrapolating to pB = 0 at 53 at. % of copper. This value is in good agreement with that obtained by Meyer & Wolff (1958), and contrary to that based on the familiar measurements of Alder (1916). The reduced magnetization-temperature curves of some of the alloys are given and these show a continuous marked decrease in fullness with increasing copper content.