Spin-lattice coupling phase transition and phonon anomalies in bismuth ferrite BiFeO3
| Autor: | Yi Ting, V.H. Schmidt, Pin-Yi Chen, Cheng-Sao Chen, Zhe-Rui Xu, Chi-Shun Tu |
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| Rok vydání: | 2016 |
| Předmět: |
Phase transition
Materials science Condensed matter physics Mechanical Engineering Metals and Alloys 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Crystal Condensed Matter::Materials Science Magnetization chemistry.chemical_compound Tetragonal crystal system Ferromagnetism chemistry Mechanics of Materials 0103 physical sciences Materials Chemistry Condensed Matter::Strongly Correlated Electrons 010306 general physics 0210 nano-technology Single crystal Néel temperature Bismuth ferrite |
| Zdroj: | Journal of Alloys and Compounds. 687:442-450 |
| ISSN: | 0925-8388 |
| DOI: | 10.1016/j.jallcom.2016.06.193 |
| Popis: | Phase transition, phonon vibration, and magnetization in (100) BiFeO3 (BFO) multiferroic single crystals have been characterized as functions of temperature. The BFO single crystal exhibits a weak ferromagnetic hysteresis loop possibly due to appearance of ferromagnetic Fe O Fe orderings and a modulation of the Fe O Fe bond. Zero-field-cooled (ZFC) and field-cooled (FC) magnetic susceptibilities suggest a weak spin-glass behavior below ∼200 K. High-resolution transmission electron microscopy (HRTEM) suggests a rhombohedral R3c symmetry (with tilted FeO6 octahedra) and lattice distortion in the surface layer. The BFO crystal undergoes a structural transition sequence of rhombohedral−tetragonal−orthorhombic− cubic at ∼620–640, ∼1000, and ∼1100 K, respectively. The spin-lattice coupling accounts for the rhombohedral tetragonal transition upon approaching the Neel temperature (TN). The low-frequency Raman-active modes ψ4,II, E(1), A1(1), and A1(2) reveal clear softening anomalies in frequency shifts and broad peaks in full-width-at-half-maximum (FWHM) around 450 K, which is attributed to the Fe O Fe ordering transition without change of structural symmetry. |
| Databáze: | OpenAIRE |
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