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Zusammenfassung:
An AA(3)'B4O12-type transition-metal-only quadruple perovskite oxide MnCu3Mn4O12 was prepared by high-pressure and high-temperature methods. The compound has a cubic Im-3 symmetry with charge distribution of Mn2+Cu32+Mn44+O12. A long-range ferrimagnetic phase transition caused by Cu2+(up arrow)Mn4+(down arrow) spin interaction is found to occur at a Curie temperature T-C approximate to 365 K . Different from the isostructural compound CaCu3Mn4O12, the susceptibility of MnCu3Mn4O12 experiences a second anomaly similar to 200 K due to the effects of A-site Mn2+ spin ordering. Moreover, the A-site Mn2+ spins also considerably decrease the magnitude of resistivity. Theoretical calculations reveal that the A-site Mn 3d orbitals locate near the Fermi level and hybridize with the Cu 3d and O 2p orbitals, playing a crucial role on the magnetic and electrical transport properties of MnCu3Mn4O12. In this paper, we provide an interesting example using A-site magnetic ions to significantly tune the physical properties in AA(3)'B4O12-type quadruple perovskite oxides.
