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Free keywords:
Antiferromagnetism; Crystal structure; Glass; Glass transition; Iron compounds; Perovskite; Spin glass; X ray absorption spectroscopy; X rays, Antiferromagnetic phase transition; High-pressure synthesis; Mott variable-range hopping; Ordered perovskite; Soft x-ray absorption spectroscopies; Spin order; Strong electron correlations; Temperature-dependent resistivity, Manganese compounds
Abstract:
An AA’3B4O12-type perovskite oxide CaMn3(Fe3Mn)O12 was synthesized at 8 GPa and 1473 K. X-ray diffraction shows a cubic crystal structure with space group Im-3. The charge states are verified by soft x-ray absorption spectroscopy to be CaMn3+ 3(Fe3+ 3Mn4+)O12, where the Ca2+ and Mn3+ are 1:3 ordered respectively at A and A′ sites, while the Mn4+ and Fe3+ are disorderly distributed at B site. The spin interaction of A′-site Mn3+ ions causes a long-range antiferromagnetic phase transition at about 39 K. Subsequently, a spin glass transition is found to occur around 14 K due to the randomly distributed Fe3+ and Mn4+ at B site. Moreover, the spin glass behavior follows a dynamic scaling power law. The temperature dependent resistivity can be well fitted by a 3D Mott variable-range hopping model, indicating the insulating nature of CaMn3(Fe3Mn)O12 due to the strong electron correlation effects. © 2019 Elsevier Inc.
