Abstract
is the archetypal magnetoelectric (ME) material, which has a linear coupling between electric and magnetic polarizations. Quadratic ME effects are forbidden for the magnetic point group of , due to space-time inversion symmetry. In films grown by sputtering, we find a signature of a quadratic ME effect that is not found in bulk single crystals. We use Raman spectroscopy and magnetization measurements to deduce the removal of space-time symmetry and corroborate the emergence of the quadratic ME effect. We propose that metastable site-selective trace dopants remove the space, time, and space-time inversion symmetries from the original magnetic point group of bulk . We include the quadratic ME effect in a model describing the switching process during ME field cooling and estimate the effective quadratic susceptibility value. The quadratic magnetoelectric effect in a uniaxial antiferromagnet is promising for multifunctional antiferromagnetic and magnetoelectric devices that can incorporate optical, strain-induced, and multiferroic effects.
- Received 3 November 2020
- Revised 16 August 2021
- Accepted 2 September 2021
DOI:https://doi.org/10.1103/PhysRevMaterials.5.094406
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