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

The magnetic field dependence of the magnetisation ($M$) and the temperature dependence of the ac susceptibility ($χ' = dM/dH$) of CePd(1-x)Rh(x) single crystals with $0.80 \leq x \leq 0.86$ are analysed within the frame of the quantum Griffiths phase scenario, which predicts $M \propto H^λ$ and $χ' \propto T^{λ-1}$ with $0 \leq λ\leq 1$. All $M$ vs $H$ and $χ'$ vs $T$ data follow the predicted power-law behaviour. The parameter $λ$, extracted from $χ'(T)$, is very sensitive to the Rh content $x$ and varies systematically with $x$ from -0.1 to 0.4. The value of $λ$, derived from $M(H)$ measurements on a \cpr single crystal, seems to be rather constant, $λ\approx 0.2$, in a broad range of temperatures between 0.05 and 2 K and fields up to about 10 T. All observed signatures and the $λ$ values are thus compatible with the quantum Griffiths scenario.