Understanding Magnetism at the Isostructural Phase Boundary in Multiferroic BiFeO3
ORAL
Abstract
Recent study suggests that in BiFeO$_{3 }$ (BFO) thin films epitaxial strain can lead to an isostructural change from distorted rhombohedral to a distorted tetragonal structure. In this work, ferromagnetic (or pyromagnetic) phase boundaries between these two phases in BFO thin films are induced from the as-grown state or by applying electric field using piezo- response force microscopy. Rhombohedral-like BFO is a G-type antiferromagnet with its easy plane in (111)-type planes. In depth density functional theory calculations suggest that tetragonal-like BFO is a C-type antiferromagnet with its easy plane in (110)-type planes. Detailed antiferromagnetic ordering of tetragonal-like BFO has been carefully studied using photo- emission electron spectroscopy with linear polarized x-rays. The isostructural phase boundary is magnetically frustrated because the transition between G-type and C-type antiferromagnetic ordering. X-ray magnetic circular dichroism is observed using photo-emission electron microscopy and spectroscopy with circular polarized x-ray.
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Authors
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Qing He
Department of Physics, UC Berkeley
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S.-Y. Yang
Department of Physics, UC Berkeley
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R. Ramesh
University of California, Berkeley, Materials Sciences Division, Lawrence Berkeley National Laboratory, University of California Berkeley, Department of Physics, UC Berkeley
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H.-J. Lin
National Synchrotron Radiation Research Center, Taiwan, National Synchrotron Radiation Research Center
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C.-H. Wang
Department of Materials Science and Engineering, National Chiao Tung University
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Y.-H. Chu
Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu, Taiwan, Department of Materials Science and Engineering, National Chiao Tung University