Dresden 2020 – wissenschaftliches Programm
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MA 32.2: Vortrag
Mittwoch, 18. März 2020, 09:45–10:00, HSZ 401
Metastable transverse conical state in multiferroic BiFeO3 — •Boglarka Toth1, Daniel Gergely Farkas1, Jonathan S. White2, Istvan Kezsmarki3, Toshimitsu Ito4, and Sandor Bordacs1 — 1Budapest University of Technology and Economics, Physics Department — 2Paul Scherrer Institute — 3University of Augsburg — 4National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8562 Ibaraki, Japan
Magnetoelectric multiferroic materials with coexisting ferroelectric and magnetic orders have received much attention as they may find applications in low power consumption magnetoelectric memories and data storage devices. Among these materials, BiFeO3 is a unique compound as it is multiferroic even at room temperature, which is essential for future applications. Although BiFeO3 is the most studied multiferroic material, its magnetic phase diagram is not fully understood. Due to the ferroelectric distortion, the so-called Dzyaloshinskii-Moriya interaction is allowed, which, competing with the Heisenberg interaction, results in a cycloidal structure below TN = 640 K in zero field. We investigated the magnetic phases above room temperature using magnetization measurements and small-angle neutron scattering (SANS) and found a transverse conical state between the zero-field cycloidal state and the high field canted antiferromagnetic phase. Furthermore, the conical state with large magnetoelectric effect remains (meta)stable in zero-field after decreasing the magnetic field.