MAGNETIC-BEHAVIOR OF DILUTE RH IMPURITIES IN AU1-XFEX ALLOYS - A PERTURBED-ANGULAR-CORRELATION STUDY

We have studied the local magnetic behavior of isolated Rh impurities in Au1-xFex alloys for compositions x=0.01, 0.03, 0.10, and 0.18, using the time-differential perturbed-angular-correlation (TDPAC) method and by electronic structure calculations within the local spin-density (LSD) approximation. From the measured Curie-Weiss local susceptibility of the Rh100 probe as well as the LSD calculations we find large stable magnetic moments 0.5-1.0μB on Rh for compositions x0.10. In low Fe concentration alloys the observed weak local susceptibility can be reconciled with the calculated large local moments, both positive and negative, on Rh in terms of a typical Ruderman-Kittel-Kasuya-Yosida (RKKY)-type mechanism between Fe and Rh. In the reentrant spin-glass regime, T≤60 K for x=0.18, the hyperfine field Bhf shows a two-step temperature dependence, increasing sharply below 60 K, such that its extrapolated value at 0 K is enhanced by 30% over its saturated value in the ferromagnetic region. © 1994 The American Physical Society.