Dynamic magnetoelectric phenomena with electromagnons in rare-earth borate multiferroics

作者：Mukhin A A^*; Kuzmenko A M; Ivanov V Yu; Pimenov A G; Shuvaev A M; Dziom V E

来源：Physics-Uspekhi, 2015, 58(10): 993-1001.

DOI：10.3367/UFNe.0185.2015101.1089

• magnetoelectric phenomena
• multiferroics
• magnetic excitations
• magnetic spectroscopy
• antiferromagnetic resonance

Electroactive spin excitations (electromagnons), an analog of the low-frequency quasiferromagnetic antiferromagnetic resonance (AFMR) mode in 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 static (quasistatic) 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 c-axis, k parallel to c, in a transverse magnetic field H parallel to a and is accompanied by 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 parallel to b-axis, which show up in transmission asymmetry between the forward (k parallel to c) and backward (k parallel to -c) directions, being equivalent to the sign change of the magnetic field, H-b -> -H-b. A theory is developed which explains the observed dynamic magnetoelectric phenomena quantitatively by taking into consideration different symmetries of the tensors of magnetic, magnetoelectric, and dielectric susceptibilities for H parallel to a and H parallel to b.

• 出版日期2015