Anomalous nuclear magnetic susceptibility of platinum powder

Abstract

The nuclear magnetic susceptibility of platinum powder has been measured in magnetic fields of 6.8, 13.7, and 27.4 mT as a function of temperature in the range 1--20 mK, as determined by the melting curve of $^{3}\mathrm{He}$. The susceptibility does not follow a Curie law, but the anomalous behavior at 13.7 and 27.4 mT fits a Curie-Weiss law with a field-dependent Weiss constant. The spin-lattice relaxation time does not conform to a Korringa relation. The results can explain the discrepancies in the pressure dependence of the transition temperature of superfluid $^{3}\mathrm{He}$ measured by different groups.