AC susceptibility of PdNi through the ferromagnetic percolation threshold

Abstract

Detailed measurements of the field and temperature dependent AC susceptibility of a number of PdNi alloys containing between 2 and 5 at.% Ni are presented. In ferromagnetic samples attempts are made to analyse these data for Curie temperatures and critical exponent values. It is demonstrated, however, that spin-orbit induced anisotropy associated with a Ni orbital moment precludes reliable estimates for exponents, although Curie temperatures can be determined. Despite such difficulties these data are shown to be consistent not only with a previous suggestion that a spin-glass ground state would appear at low Ni concentration if complications due to the Kondo effect were not present, but also with assigning a low spin value (S=¹/₂) to the Ni site.