Magnetoelastic Coupling in the Multiferroic BiFeO3

Published June 23, 2021

Normalized transmission through a BiFeO3 crystal with the magnetic field.

High-resolution electron magnetic resonance studies of the spin-wave spectrum in the high-field phase of the multiferroic Bismuth ferrite (BiFeO₃) reveal direct evidence for the magnetoelastic coupling through a change in lattice symmetry from rhombohedral to monoclinic. This study provides important information for designing future spintronics devices based on BiFeO₃.

What did scientists discover?

Magnetic resonance spectroscopy at terahertz frequencies and magnetic fields to 35T were used to learn how electron spins interact with each other and with the crystal lattice in BiFeO₃. The spectrum varies with magnetic field orientation, implying that the spins are not simply embedded passively into the crystal, but act back to deform the lattice when the magnetic structure changes.

Why is this important?

Multiferroics that respond to both magnetic and electrical stimuli are candidate materials to replace silicon in future logic devices. BiFeO₃ is one of the few multiferroics that retains suitable properties to above room temperature. It has an exotic magnetic structure that is destroyed by magnetic fields above 18T. Spectroscopy of the simpler high-field magnetic state, which had not been studied in detail before, reveals how the lattice deformation couples to the magnetism, providing important information for designing future logic devices based on BiFeO₃.

Who did the research?

T. Rõõm,¹ J. Viirok,¹ L. Peedu,¹ U. Nagel,¹ D.G. Farkas,² D. Szaller,^2,3 V. Kocsis,^2,4 S. Bordács,² I. Kézsmárki,^2,5 D.L. Kamenskyi,⁶ H. Engelkamp,⁶ M. Ozerov,⁷ D. Smirnov,⁷ J. Krzystek,⁷ K. Thirunavukkuarasu,^7,8 Y. Ozaki,⁹ Y. Tomioka,⁹ T. Ito,⁹ T. Datta,¹⁰ and R.S. Fishman¹¹

¹NICPB, Tallinn; ²MTA-BME Budapest; ³ISSP Vienna; ⁴RIKEN Japan; ⁵IoP Augsburg; ⁶HFML-EMFL Nijmegen; ⁷National MagLab FSU; ⁸FAMU; ⁹AIST Tsukuba Japan; ¹⁰Augusta University; ¹¹ORNL

Why did they need the MagLab?

Magnetic fields above 18T are needed to destroy the magnetic structure in BiFeO₃, but fields well above 18T are not achievable in commercial magnets. The MagLab also has spectrometers covering the terahertz frequency range needed for these investigations.

Details for scientists

View or download the expert-level Science Highlight, Magnetoelastic Coupling in the Multiferroic BiFeO₃
Read the full-length publication, Magnetoelastic distortion of multiferroic BiFeO₃ in the canted antiferromagnetic state, in Phys. Rev. B

Funding

This research was funded by the following grants: G.S. Boebinger (NSF DMR-1644779); European Union; Estonian Ministry of Education; Estonian & Hungarian Academy of Science; Austrian Science Fund; Deutsche Forschungsgemeinschaft (DFG); and DOE BES (DE-AC05-00OR22725)

For more information, contact Stephen Hill.