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

TL;DR

This study investigates the magnetic properties of Ni$_{1-x}$V$_x$ alloy near its ferromagnetic quantum critical point, revealing signatures consistent with a quantum Griffiths phase through power-law behaviors and $H/T$ scaling.

Contribution

It provides experimental evidence of quantum Griffiths phase signatures in a d-metal alloy near its quantum critical point, including detailed analysis of power-law exponents and phase boundaries.

Findings

Power-law dependencies in magnetization near criticality

Observation of $H/T$ scaling over wide temperature and field ranges

Exponents vary with V concentration and align with Griffiths phase predictions

Abstract

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 $H/T$ 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.