Abstract
We demonstrate that small but finite ferroelectric polarization () emerges in orthorhombic () at ( K) because of commensurate () and collinear magnetic structure. The synchrotron x-ray and neutron diffraction data suggest that the polarization could originate from enhanced bond covalency together with subtle contribution from the lattice. The theoretical calculations indicate enhancement of bond covalency as well as the possibility of structural transition to the polar phase below . The phase, in fact, is found to be energetically favorable below in orthorhombic ( with very small energy difference) than in isostructural and nonferroelectric or . Application of electric field induces finite piezostriction in via electrostriction resulting in clear domain contrast in piezoresponse force microscopy images.
1 More- Received 29 August 2017
- Revised 4 September 2019
DOI:https://doi.org/10.1103/PhysRevB.100.195116
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