Pinning, rotation, and metastability of cycloidal domains in a magnetic field
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division
Earlier models for the room-temperature multiferroic BiFeO3 implicitly assumed that a very strong anisotropy restricts the domain wave vectors q to the threefold-symmetric axis normal to the static polarization P. However, recent measurements demonstrate that the domain wave vectors q rotate within the hexagonal plane normal to P away from the magnetic field orientation m. In this paper, we show that the previously neglected threefold anisotropy K3 restricts the wave vectors to lie along the threefold axis in zero field. Taking m to lie along a threefold axis, the domain with q parallel to m remains metastable below Bc1≈7 T. Due to the pinning of domains by nonmagnetic impurities, the wave vectors of the other two domains start to rotate away from m above 5.6 T, when the component of the torque τ=M×B along P exceeds a threshold value τpin. Since τ=0 when m⊥q, the wave vectors of those domains never become completely perpendicular to the magnetic field. Our results explain recent measurements of the critical field as a function of field orientation, small-angle neutron scattering measurements of the wave vectors, as well as spectroscopic measurements with m along a threefold axis. Finally, the model developed in this paper also explains how the three multiferroic domains of BiFeO3 for a fixed P can be manipulated by a magnetic field.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- AC05-00OR22725
- OSTI ID:
- 1422612
- Alternate ID(s):
- OSTI ID: 1415531
- Journal Information:
- Physical Review. B, Vol. 97, Issue 1; ISSN 2469-9950
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Progress in BiFeO 3 -based heterostructures: materials, properties and applications
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journal | January 2020 |
Direct coupling of ferromagnetic moment and ferroelectric polarization in BiFeO 3
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journal | October 2019 |
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