Features of the magnetization in ceramics Bi0.86Sm0.14Fe1-xMnxO3 in the rhombohedral - orthorhombic morphotropic phase boundary

Abstract

Crystal structure of the ceramic compounds Bi0.86Sm0.14Fe1-xMnxO3 prepared by solid state reaction method was studied using X-ray diffraction, scanning electron microscopy and Raman spectroscopy; magnetometry measurements were performed to study magnetic properties and to investigate a correlation between the magnetic and crystal structures of the compounds. The compounds with 0 = x ≤ 0.1 are characterized by the coexistence of the polar rhombohedral and the antipolar orthorhombic phases, an increase of Mn doping causes a stabilization of the orthorhombic phase. Room temperature magnetization data show a gradual reduction of the remanent magnetization with an increase of Mn concentration, while a decrease of temperature causes a nontrivial reduction of remanent magnetization which is determined by a transformation of the non-collinear antiferromagnetic structure towards the collinear antiferromagnetic structure. The magnetic state of the compounds notably depends on the phase ratio of the coexisting structural phases and consists of the antiferromagnetic phases associated with the respective rhombohedral and the orthorhombic phases as well as the ferromagnetic component associated with the phase boundary spins. An evolution of the mentioned magnetic subsystems is discussed as a function of the chemical composition and temperature.