We show that nonrelativistic exchange interactions and spin fluctuations can give rise to a linear magnetoelectric effect in collinear antiferromagnets at elevated temperatures that can exceed relativistic magnetoelectric responses by more than 1 order of magnitude. We show how symmetry arguments, ab initio methods, and Monte Carlo simulations can be combined to calculate temperature-dependent magnetoelectric susceptibilities entirely from first principles. The application of our method to ${\mathrm{Cr}}_2{\mathrm{O}}_3$ gives quantitative agreement with experiment.

• Received 12 April 2010

DOI:https://doi.org/10.1103/PhysRevLett.105.087202