Structural and physical properties of Ni 1−x V x alloys around and away from quantum critical point

Abstract

We investigate the room temperature structure (global and local), temperature dependent magnetic and transport behaviour of Ni 1−x V x ( 0⩽x⩽0.13 ) alloys. Our Energy Dispersive Analysis of x-rays results show that the prepared compositions are stoichiometric. With increase in V doping, the compounds exhibit a quantum phase transition around x c = 0.12, where the ferromagnetic phase is suppressed. Our results show that all the compounds stabilize in face centred cubic structure at RT and the lattice parameter shows unusual behaviour close to x c . The magnetic and heat capacity studies show signature of Griffiths phase on either side of x c . From 25 K to the lowest collected temperature, we observe a linear T dependence of resistivity at x = 0.1 and around x c , which is separated by a Fermi-liquid region around x = 0.106. This suggests that the origin of the transport behaviour is different around the quantum critical point and away from it. Our Ni K-edge x-ray Absorption Spectroscopy results show that there is a significant reduction in the first coordination number around Ni central atom on doping. Further, with doping, there is distortion in the first coordination shell around Ni. This suggests, with V doping, the local structure around Ni is different from the global structure as obtained from the x-ray Diffraction results. Interestingly, with doping, we observe a direct connection between the extent of distortion at RT and the magnetic disorder obtained at 2 K. We believe our results will motivate the scientific community to further study the interplay between the structural disorder and quantum fluctuations with temperature at the local level.