Mössbauer studies of multiferroics BiFe1 – x Cr x O3 (x = 0–0.20)

Abstract

The Mossbauer studies on 57Fe nuclei in multiferroics BiFe1 – x Cr x O3 (x = 0.05, 0.10, and 0.20) have been performed at room temperature. The multiferroics BiFe1 – x Cr x O3 (x = 0.05, 0.10, and 0.20) with the rhombohedral R3c structure have been prepared by solid-state synthesis under high pressures. The effect of substitution of Cr cations for Fe cations on the spatial spin-modulated structure, and also hyperfine electrical and magnetic interactions of 57Fe nuclei has been studied. The substituted ferrites demonstrate an anharmonic modulated spin structure of cycloid type, in which iron atoms with different cation environments take part. The anharmonism parameter of the cycloid linearly increases from m = 0.10 at x = 0 to m = 0.78 ± 0.02 at x = 0.20. The constants of magnetic uniaxial anisotropy K u are estimated at room temperature: K u ≈ 0.36 × 106 erg/cm3 at x = 0 and K u ≈ 4.22 × 106 erg/cm3 at x = 0.20.