Abstract
The magnetic field induced rearrangement of the cycloidal spin structure in ferroelectric monodomain single crystals of the roomerature multiferroic BiFeO3 is studied using small-angle neutron scattering. The cycloid propagation vectors are observed to rotate when magnetic fields applied perpendicular to the rhombohedral (polar) axis exceed a pinning threshold value of ∼5 T. In light of these experimental results, a phenomenological model is proposed that captures the rearrangement of the cycloidal domains, and we revisit the microscopic origin of the magnetoelectric effect. A new coupling between the magnetic anisotropy and the polarization is proposed that explains the recently discovered magnetoelectric polarization perpendicular to the rhombohedral axis.
| Original language | English |
|---|---|
| Article number | 147203 |
| Journal | Physical Review Letters |
| Volume | 120 |
| Issue number | 14 |
| DOIs | |
| State | Published - Apr 5 2018 |
Funding
We are grateful to R. S. Fishman, T. Rõõm, U. Nagel, and D. Szaller for fruitful discussions. This work was supported by Hungarian Research Funds OTKA K 108918, OTKA PD 111756, National Research, Development and Innovation Office—NKFIH, ANN 122879, Bolyai 00565/14/11, the Swiss National Science Foundation (SNF) via the Sinergia network "NanoSkyrmionics" (Grant No. CRSII5-171003) and the SNF Project Grant No. 153451, the Deutsche Forschungsgemeinschaft (DFG) via the Transregional Research Collaboration TRR 80: From Electronic Correlations to Functionality (Augsburg-Munich-Stuttgart). This work is based on neutron experiments performed at the Institut Laue-Langevin (ILL), Grenoble, France and the Paul Scherrer Institut, Villigen, Switzerland. A portion of this research used resources at the High Flux Isotope, a Department of Energy (DOE) Office of Science User Facility operated by the Oak Ridge National Laboratory.