Influence of magnetic interactions on the magnetic properties of dilute AuMn alloys

Abstract

We have measured the initial susceptibility $\ensuremath{\chi}$ and magnetization $M$ up to $H=50$ kG of a series of AuMn alloys ($n=50\ensuremath{-}2000\ensuremath{-}\mathrm{p}\mathrm{p}\mathrm{m}$ Mn) from 1.2 to about 100 K. Our results for $\ensuremath{\chi}$ and $M$ obey quite well the scaling laws predicted for magnetic impurities which interact via the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction, viz., $\ensuremath{\chi}(n,T)={F}_{1}(\frac{T}{n})$ and $\frac{M(n,T,H)}{n}={F}_{2}(\frac{T}{n},\frac{H}{n})$. From the observed decrease of the magnetization per impurity atom as the Mn concentration increases, ${V}_{0}=(2.4\ifmmode\pm\else\textpm\fi{}0.3)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}37}$ erg ${\mathrm{cm}}^{3}$ is determined for the strength of the RKKY interaction, $V(r)=\frac{({V}_{0}cos2{k}_{F}r)}{{r}^{3}}$. The observed approach to saturation of $M$ is also consistent with this value for ${V}_{0}$. For the spin per Mn atom we find $S=2.25\ifmmode\pm\else\textpm\fi{}0.1$, assuming $g=2$.