LOW-FIELD SUSCEPTIBILITY OF PTFE ALLOYS

The temperature dependence of the low field AC susceptibility of a number of PtFe alloys has been measured. For ferromagnetic alloys the Curie temperature varies linearly with the solute concentration (up to approximately 15% Fe) and extrapolates to zero at a critical concentration of 0.76% Fe. Below this concentration a spin glass regime probably exists. The susceptibility- temperature curves for the weakly ferromagnetic alloys (1-4% Fe) are similar to those hitherto commonly associated only with spin glasses, while for the most concentrated alloys investigated (15 and 17% Fe) the curves bear some resemblance to those of AuFe alloys of similar compositions.