Crystal structure transformation and improved dielectric and magnetic properties of La-substituted BiFeO3 multiferroics |
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| Affiliation: | 1. Department of Physics, Guru Jambheshwar University of Science & Technology, Hisar 125001, Haryana, India;2. Materials Research Laboratory, Department of Physics, Deenbandhu Chhotu Ram University of Science & Technology, Murthal 131039, Haryana, India;1. Materials Research Laboratory, Department of Physics, Deenbandhu Chhotu Ram University of Science & Technology, Murthal 131039, India;2. Nanomaterials Research Laboratory, Department of Materials Science and Nanotechnology, Deenbandhu Chhotu Ram University of Science & Technology, Murthal 131039, India;3. Materials Science Research Laboratory, Department of Applied Physics, Guru Jambheshwar University of Science & Technology, Hisar 125001, India;1. Materials Research Laboratory, Department of Physics, Deenbandhu Chhotu Ram University of Science and Technology, Murthal 131039, India;2. Department of Applied Physics, Guru Jambheshwar University of Science and Technology, Hisar 125001, India;1. School of Physics and Electronic Information, Luoyang Normal College, Henan, Luoyang 471022, PR China;2. The Beijing Key Laboratory for Nanophotonics and Nanostructure, Department of Physics, Capital Normal University, Beijing 100048, PR China;3. Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072, China;4. School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, PR China;1. Department of Physics, Guru Jambheshwar University of Science & Technology, Hisar 125001, Haryana, India;2. Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600036, India |
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| Abstract: | Samples of Bi1−xLaxFeO3 with x = 0.1, 0.3, 0.5, and 0.7 have been synthesized by two stage solid state reaction method. Structural characterization was performed using powder x-ray diffraction at room temperature. The crystal structure of perovskite phases are further characterized via Rietveld analysis which revealed a structural transition from R3c symmetry of the parent phase of BiFeO3 to orthorhombic Pnma symmetry of LaFeO3. However the intermediate samples with x = 0.3 and 0.5 are bi – phasic (i.e. a combination of rhombohedral R3c and orthorhombic Pbam phases co-exist). Rietveld Refinement presents a good agreement between measured and simulated patterns. The transition from a rhombohedral to orthorhombic unit cell is suggested to be driven by the dilution of the stereochemistry of the lone pair of Bi3+ at A- site. M-H hysteresis loops are recorded at room temperature up to a field of 15 kOe. The G-type antiferromagnetic spin structure and the magnetic moment are very sensitive to increasing La concentration at A-site. La substitution transformed antiferromagnetic BiFeO3 into ferromagnetic which is closely related to the structural phase transition and modification of antiparallel spin structure. Dielectric constant (ε′) and dissipation factor (tan δ) measured in frequency range 1 kHz to 5 MHz showed dispersion behaviour at low frequencies. |
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| Keywords: | Multiferroics X-ray diffraction Rietveld refinement Magnetic properties Dielectric properties |
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