Neutron diffraction and Mössbauer studies on Fe1−xCr2S4(x=0.0, 0.04, 0.08)

Abstract

Polycrystalline samples of Fe1−xCr2S4(x=0.0, 0.04, 0.08) have been studied with x-ray and neutron powder diffraction, Mössbauer spectroscopy, magnetization, and magnetoresitance (MR) measurements. Neutron diffraction patterns were obtained at various temperature ranges from 10 K to room temperature. Neutron diffraction on FeCr2S4 above 10 K shows that there is no crystallographic distortion and reveals antiferromagnetic ordering, with the magnetic moment of Fe+2 (−3.52 μB) aligned antiparallel to Cr3+ (2.72 μB). Mössbauer spectra shows asymmetric line broadening in the temperature range from 13 to 170 K and it is considered to be dynamic Jahn–Teller stabilization. The charge states of the iron ions are ferrous in character. With increasing Fe deficiency, the peak of maximum magnetoresistance of x=0.0, 0.04, and 0.08, occurred at 171, 174, and 186 K, respectively. The increasing temperature of the MR peak position is interpreted as due to an enhancement of activation energy.