Low-Temperature Magnetization in Very Dilute Palladium-Iron Alloys

Abstract

The magnetization curves of alloys containing 0.15, 0.10, 0.07, 0.05, and 0.01 at. % iron and two specimens of palladium of different purity have been measured in the temperature range 1.2° to 4.2°K in homogeneous fields up to 18.5 kG. The curves have been analyzed and expressed by an equation of the form σ= χH′+σL= χH′+σ0f(H′/T),where H′=H+Dσ is the sum of the applied field H and Dσ an internal field. The values of χ required are of the order of that for pure palladium and the values of D range from 6×103 to 8×103. The f(H′/T) corresponds closely to Brillouin functions with values of gJ ranging from 9 for the most dilute alloy to 20 for the most concentrated. A possible reason for this behavior is suggested. Curie temperatures have also been estimated for the alloys using the method described by Arrott (1957) restricted to values of σL for which the expansion in σL/σ0 is converging fairly rapidly. The Curie temperature found for the 0.15 at. % iron alloy is 2.12°K, agreeing well with the indications of resistivity and specific-heat measurements.