We report on the synthesis and characterization of BiFe0.5Mn0.5O3, a potential type-I multiferroic compound displaying temperature-induced magnetization reversal. Bulk samples were obtained by means of solid-state reaction carried out under the application of hydrostatic pressure of 6 GPa at 1100 ◦C. The crystal structure is a highly distorted perovskite with no cation order on the B site, where, besides a complex scheme of tilt and rotations of the TM-O6 octahedra, large off-centering of the bismuth ions is detected. Below T1 = 420 K the compound undergoes a first weak ferromagnetic transition related to the ordering of iron-rich clusters. At lower temperatures (just below RT) a complex thermally activated mechanism induces at first an enhancement of the magnetization at T2 = 288 K, then a spontaneous reversal giving rise to a negative response. The complementary use of powder neutron diffraction, superconducting quantum interference device magnetometry, and M¨ossbauer spectroscopy allowed us to propose as a possible interpretation of the overall magnetic behavior the presence of an uncompensated competitive coupling between nonequivalent clusters of weakly ferromagnetic interactions characterized by different critical temperatures and resultant magnetizations.
Thermally activated magnetization reversal in bulk BiFe0.5Mn0.5O3 / D. Delmonte; F. Mezzadri; C. Pernechele; G. Calestani; G. Spina; M. Lantieri; M. Solzi; R. Cabassi; F. Bolzoni; A. Migliori; C. Ritter; E. Gilioli. - In: PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS. - ISSN 1098-0121. - 88(2013), pp. 014431-1-014431-11. [10.1103/PhysRevB.88.014431]
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