Complex strain evolution of polar and magnetic order in multiferroic BiFeO<sub>3</sub> thin films.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 30242162.
- Also identified by DOI 10.1038/s41467-018-06190-5 and PMC identifier 6155110.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Electric-field control of magnetism requires deterministic control of the magnetic order and understanding of the magnetoelectric coupling in multiferroics like BiFeO<sub>3</sub> and EuTiO<sub>3</sub>. Despite this critical need, there are few studies on the strain evolution of magnetic order in BiFeO<sub>3</sub> films. Here, in (110)-oriented BiFeO<sub>3</sub> films, we reveal that while the polarization structure remains relatively unaffected, strain can continuously tune the orientation of the antiferromagnetic-spin axis across a wide angular space, resulting in an unexpected deviation of the classical perpendicular relationship between the antiferromagnetic axis and the polarization. Calculations suggest that this evolution arises from a competition between the Dzyaloshinskii-Moriya interaction and single-ion anisotropy wherein the former dominates at small strains and the two are comparable at large strains. Finally, strong coupling between the BiFeO<sub>3</sub> and the ferromagnet Co<sub>0.9</sub>Fe<sub>0.1</sub> exists such that the magnetic anisotropy of the ferromagnet can be effectively controlled by engineering the orientation of the antiferromagnetic-spin axis.