[Zurück]

A. Mukhin, A. Kuzmenko, V. Yu. Ivanov, A. Pimenov, A. M. Shuvaev, V. Dziom:
"Dynamic magnetoelectric phenomena within electromagnons in rare-earth borate multiferroics";
PHYSICS-USPEKHI, 58 (2015), S. 1089 - 1098.

Electroactive spin excitations (electromagnons), an analog of the low-frequency quasiferromagnetic antiferromagnetic resonance (AFMR) mode in a Fe subsystem, are observed in multiferroic rare-earth ferroborates (specifically in SmFe3(BO3)4) in the frequency range of 40-150 GHz, which are shown to contribute dominantly to the giant quasi-static magnetodielectric effect and which produce two types of dynamic magnetoelectric effects: (a) giant optical activity, which occurs for the wave vector k parallel to the crystallographic axis c, k || c, in a transverse magnetic field H || a and which involves polarization plane rotation by more than 70 deg mm−1 in the resonance; and (b) directional birefringence and dichroism in a transverse magnetic field H || b-axis, which show up in radiation transmission asymmetry between the forward k || c) and backward k || c) directions, which is equivalent to the sign change Hb → −Hb. A theory is developed which explains the observed dynamic magnetoelectric phenomena quantitatively by taking into consideration the different symmetry of the tensors of magnetic, magnetoelectric and dielectric susceptibilities for H || a and H || b.

http://dx.doi.org/10.3367/UFNe.0185.201510l.1089