The in-plane ferromagnetic ordering in half-metallic CuCr2 Se4-x Brx (x=0.25) single crystal

The transport property of chalcogenide spinel CuCr2 Se-4 with an itinerant ferromagnetic ground state can be modulated by doping of bromine, where the half-metallic state can be realized around x = 0.25 in CuCr2 Se4-x Br-x system. In this work, the single crystal CuCr2 Se4-x Br-x (x = 0.25) with the cleave surface (111) plane has been investigated by the electron paramagnetic resonance (EPR) spectroscopy. The EPR results show that the in-plane magnetization is strong while the out-of-plane one is weak, which indicate that the spins are ferromagnetic ordered within the (111) plane. In addition, the isothermal EPR spectra in the ferromagnetic phase display that the spin coupling strength (lambda) and crystal field (Delta(CF)) depend on the rotation angle phi as relation lambda/Delta(CF). cos phi. Moreover, the peak-to-peak linewidth Delta H-PP increases linearly with the decrease of temperature, which suggests that the spin-orbit coupling is enhanced linearly with temperature cooling. (C) 2016 Elsevier B.V. All rights reserved.