Signatures of a quantum Griffiths phase in a d-metal alloy close to its ferromagnetic quantum critical point

We report magnetization ($M$) measurements close to the ferromagnetic quantum phase transition of the d-metal alloy Ni${}_{1-x}$V${}_x$ at a vanadium concentration of $x_c\approx 11.4$. In the diluted regime ($x>x_c$), the temperature ($T$) and magnetic field ($H$) dependencies of the magnetization are characterized by nonuniversal power laws and display $H\mathrm{/}T$ scaling in a wide temperature and field range. The exponents vary strongly with $x$ and follow the predictions of a quantum Griffiths phase. We also discuss the deviations and limits of the quantum Griffiths phase as well as the phase boundaries due to bulk and cluster physics.