Quantum Griffiths phase in CePd(1-x)Rh(x) with x ~ 0.8

Abstract

The magnetic field dependence of the magnetisation ($M$) and the temperature dependence of the ac susceptibility ($\ddot{I}{‡}^{\prime }=dM/dH$) of CePd(1-x)Rh(x) single crystals with $0.80\le x\le 0.86$ are analysed within the frame of the quantum Griffiths phase scenario, which predicts $M\propto H^{\hat{I}}»$ and $\ddot{I}{‡}^{\prime }\propto T^{\hat{I}»-1}$ with $0\le \hat{I}»\le 1$. All $M$ vs $H$ and $\ddot{I}{‡}^{\prime }$ vs $T$ data follow the predicted power-law behaviour. The parameter $\hat{I}»$, extracted from $\ddot{I}{‡}^{\prime }(T)$, is very sensitive to the Rh content $x$ and varies systematically with $x$ from -0.1 to 0.4. The value of $\hat{I}»$, derived from $M(H)$ measurements on a \cpr single crystal, seems to be rather constant, $\hat{I}»\approx 0.2$, in a broad range of temperatures between 0.05 and 2 K and fields up to about 10 T. All observed signatures and the $\hat{I}»$ values are thus compatible with the quantum Griffiths scenario.

4 pages, 3 figures