Magnetoelastic tuning of the antiferromagnetic resonances in orthoferrites

The stress dependences of the two-sublattice antiferromagnetic resonance frequencies in orthoferrites are formulated and estimated for the case of longitudinal stress. With the lower frequency mode, a stress dependence of a few MHz/bar is expected, due primarily to the stress dependence of the in-plane anisotropy. In the temperature region of spontaneous spin rotation, this effect should be much larger. The tuning of the upper mode is expected to be of the order of tens of MHz/bar. This is due largely to the stress dependence of the antisymmetric exchange, and to a lesser degree, to the magnetoelasticity of the out-of-plane anisotropy.