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  Karpinsky, D.V.; Troyanchuk, I.O.; Bushinsky, M.V.; Ignatenko, O.V.; Silibin, M.V.; Gavrilov, S.A.; Franz, A.: Structural and magnetic phase transitions in Bi_1-xCa_xFe_1-xMn_xO₃ multiferroics. Journal of Alloys and Compounds 692 (2017), p. 955-960

10.1016/j.jallcom.2016.09.091

Abstract:
Crystal and magnetic structure of Bi1−xCaxFe1−xMnxO3 (x ≤ 0.3) multiferroics have been studied by X-ray and neutron powder diffraction as well as magnetometry techniques. It was shown that polar rhombohedral phase specific for the compounds with x ≤ 0.19 transforms to the nonpolar orthorhombic one through very narrow (∼1% on concentration) two phase structural state. The polar phase is characterized by antiferromagnetic structure, wherein the compounds with x ≤ 0.1 show metamagnetic behavior. Compounds with x ≥ 0.1 having polar rhombohedral structure exhibit small remnant magnetization (up to 0.07 emu/g for x = 0.17 compound). Structural transition into the nonpolar orthorhombic phase does not change significantly the magnetic structure of the compounds. However temperature decrease down to 10 K leads to notable change in magnetic anisotropy and spontaneous magnetization. The magnetic properties of the compounds are discussed assuming their inhomogeneous magnetic state affected by external magnetic field and temperature.