Effect of Mn substitution on the crystal and magnetic structure of Bi1-xCaxFeO3-x/2 multiferroics

The room- and low-temperature neutron diffraction measurements of the Bi0.9Ca0.1Fe0.6Mn0.4O3+delta compound have been carried out to disclose the influence of Mn substitution on the multiferroic properties of the low-doped Bi1-xCaxFeO3-x/2 perovskites combining ferroelectric and weak ferromagnetic behavior. It has been proven that the material under study retains a polar R3c structure specific to the parent Bi0.9Ca0.1FeO2.95. The Mn doping results in the elimination of oxygen vacancies giving rise to the increase in spontaneous electric polarization. The chemical modification stabilizes the collinear antiferromagnetic structure at room temperature. The reorientation of the antiferromagnetic vector from the c to a axis takes place with decreasing temperature. Reflecting the competitive character of the superexchange interactions between Fe3+, Mn3+ and Me4+, the coexistence of ferromagnetic glassy and antiferromagnetic long-range-ordered phases is observed at low temperatures. (C) 2020 Elsevier B.V. All rights reserved.