Symmetry Mismatch Controls Magnetism ​in a Ferroelastic Film​

February 2, 2020
Symmetry Mismatch Controls Magnetism ​in a Ferroelastic Film​
(a) Schematic illustration of PNR geometry measured on LCO film showing magnetization enhanced away from the interfaces. (b) PNR data for two polarizations. (c) Fitted nuclear SLD. (d) Magnetic SLD.​

Scientific Achievement

The magnetization depth profile of LaCoO3 (LCO) films shows that pressure reduces the magnetization, confirming that a symmetry mismatch at the interface leads to the  unexpected ferromagnetism (FM).​

Significance and Impact

The results give new insights into the control of magnetism in thin films of  ferroelastic materials, pointing to next generation devices such as strain sensors.​

Research Details

  • Polarized neutron reflectometry (PNR) was measured using a new pressure cell.​
  • The origin of FM was found to be higher spin state Co3+ in low density regions away from the mismatched interface; pressure increases the density producing non-magnetic low spin Co3+.​

"Exploiting Symmetry Mismatch to Control Magnetism in a Ferroelastic Heterostructure,"

Er-Jia Guo, Ryan Desautels, Dongkyu Lee, Manuel A. Roldan, Zhaoliang Liao, Timothy Charlton, Haile Ambaye, Jamie Molaison, Reinhard Boehler, David Keavney, Andreas Herklotz, T. Zac Ward, Ho Nyung Lee, and Michael R. Fitzsimmons

Phys. Rev. Lett. 122, 187202 – Published 8 May 2019 DOI: