Non-Fermi liquid behavior and signature of Griffiths phase in Ni-Cr binary alloy

Abstract

Detailed magnetic, electrical, and thermal property measurements have been carried out on Ni100-xCrx binary alloys, mainly to study the effect of Cr. The following points emerge from this study: with the increase in Cr concentration, magnetic moment and Curie temperature linearly decreased and the ferromagnetic order is completely suppressed at the critical concentration (xcr ≈ 12.16 ± 0.03). The Rhodes-Wohlfarth ratio increases as the concentration approaches xcr, suggesting a weak itinerant ferromagnetic character of NiCr compositions (x < xcr). Analysis of low-temperature electrical resistivity and specific heat data suggests that the spin fluctuation's contribution increases and the Fermi-liquid behavior breaks down as the concentration approaches xcr. For x ∼xcr, the dc susceptibility χ(T) deviates from the Curie-Weiss law reminiscent to that of the Griffiths phase. The low-temperature magnetic isotherms of Ni-Cr follow power law, M (H) = M 0 + d λ H λ, and the non-universal exponent (λ) shows a minimum at xcr ∼12. Further, temperature dependence of magnetization studies also support the presence of the quantum Griffiths phase, similar to that reported in the Ni-V alloy system. The temperature dependencies of the electrical resistivity, magnetization, and specific heat follow the theoretical predictions of a quantum critical point within experimental uncertainties.