Evidence for magnetic clusters in Ni1-xVx close to the quantum critical concentration

International Conference on Strongly Correlated Electron Systems 2014

Wang, R.^1 ; Ubaid-Kassis, S.^1 ; Schroeder, A.^1 ; Baker, P.J.^2 ; Pratt, F.L.^2 ; Blundell, S.J.^3 ; Lancaster, T.^3,4 ; Franke, I.^3 ; Möller, J.S.^3,5 ; Vojta, T.^6

Department of Physics, Kent State University, Kent

OH

44242, United States^1

ISIS Facility, STFC Rutherford Appleton Laboratory, Harwell Oxford

OX11 0QX, United Kingdom^2

Department of Physics, Clarendon Laboratory, Parks Road, Oxford

OX1 3PU, United Kingdom^3

Durham University, Centre for Materials Physics, South Road, Durham

DH1 3LE, United Kingdom^4

Neutron Scattering and Magnetism, Laboratory for Solid State Physics, ETH Zürich, Zürich

CH-8093, Switzerland^5

Department of Physics, Missouri University of Science and Technology, Rolla

MO

65409, United States^6

关键词: Critical concentration;    Ferromagnetic ground state;    Ferromagnetic orderings;    Magnetic field distribution;    Power law distribution;    Quantum phase transitions;    Temperature dependence;    Vanadium concentration;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/592/1/012089/pdf
DOI  :  10.1088/1742-6596/592/1/012089

来源: IOP

【 摘 要 】

The d-metal alloy Ni1-xVxundergoes a quantum phase transition from a ferromagnetic ground state to a paramagnetic ground state as the vanadium concentration x is increased. We present magnetization, ac-susceptibility and muon-spin relaxation data at several vanadium concentrations near the critical concentration xc∼ 11.6 % at which the onset of ferromagnetic order is suppressed to zero temperature. Below xc, the muon data reveal a broad magnetic field distribution indicative of a long-range ordered ferromagnetic state with spatial disorder. We show evidence of magnetic clusters in the ferromagnetic phase and close to the phase boundary in this disordered itinerant system as an important generic ingredient of a disordered quantum phase transition. In contrast, the temperature dependence of the magnetic susceptibility above xcis best described in terms of a magnetic quantum Griffiths phase with a power-law distribution of fluctuation rates of dynamic magnetic clusters. At the lowest temperatures, the onset of a short-range ordered cluster-glass phase is recognized by an increase in the muon depolarization in transverse fields and maxima in ac-susceptibility.