Electronic structure and magnetic properties of Al‐doped Ca2Fe2O5 brownmillerite compounds |
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| Authors: | The‐Long Phan Ngo Tran Deok Hyeon Kim Pham T Tho Bui T Huy Toan N Dang Dong‐Seok Yang Bowha Lee |
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| Affiliation: | 1. Department of Physics and Oxide Research Center, Hankuk University of Foreign Studies, Yongin, South Korea;2. Department of Chemistry, Changwon National University, Changwon, South Korea;3. Institute of Research and Development, Duy Tan University, Da Nang, Vietnam;4. Department of Science Education, Chungbuk National University, Cheongju, South Korea |
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| Abstract: | Polycrystalline Ca2Fe2?xAlxO5 (x = 0‐1.4) samples were prepared by conventional solid‐state reactions. Their crystalline/electronic structures and magnetic properties were characterized in detail. Powder X‐ray diffraction analyses revealed that the samples crystallized in orthorhombic brownmillerite‐type structures with the occurrence of the Pcmn‐Ibm2 phase separation in the region between x = 0.4 and 0.6. The results obtained from analyzing Raman scattering and X‐ray‐absorption fine‐structure spectra also indicated this phase separation. Although x in Ca2Fe2?xAlxO5 varies in a wide range from 0 to 1.4, the +3 oxidation state of Fe remained almost unchanged. Magnetization measurements revealed that all Ca2Fe2?xAlxO5 samples have weak ferromagnetic order, and both the saturation magnetization and coercive force are dependent on the temperature, x, and structure phases. |
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| Keywords: | brownmillerite crystal and electronic structures magnetism |
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