23 June 2021

Magnetoelastic Coupling in the Multiferroic BiFeO3

Normalized transmission through a BiFeO3 crystal with the magnetic field. 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.

THE TOOLS THEY USED

This research was Joint EMR/DC-Field Facility Operation Broadband Backward Wave Oscillator (BWO) Spectrometer in EMR Facility and 35 Tesla 32 mm Bore Magnet (Cell 8) in DC Field Facility

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

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.

Details

  • Research Area: Magnet Resonance Technique Development, Magnetism and Magnetic Materials
  • Research Initiatives: Energy,Materials
  • Facility / Program: EMR
  • Year: 2021
Last modified on 23 June 2021