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14 papers
CONFERENCES AND SYMPOSIA
Dynamic magnetoelectric phenomena with electromagnons in rare-earth borate multiferroics
A. A. Mukhina,
A. M. Kuzmenkoa,
V. Yu. Ivanova,
A. G. Pimenovb,
A. M. Shuvaevb,
V. E. Dziomb a Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow
b Institute of Solid State Physics, Vienna University of Technology, Vienna
Abstract:
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 SmFe
$_3$(BO
$_3$)
$_4$] 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,
$\mathbf{k} \parallel c$, in a transverse magnetic field
$\mathbf{H}\parallel a$ 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
$\mathbf{H}\parallel b$-axis, which show up in transmission asymmetry between the forward (
$\mathbf{k}\parallel c$) and backward (
$\mathbf{k} \parallel -c$) directions, being equivalent to the sign change of the magnetic field,
$H_b \to -H_b$. 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
$\mathbf{H}\parallel a$ and
$\mathbf{H} \parallel b$.
PACS:
01.10.-m,
01.10.Fv, 75.85.+t,
76.50.+g,
78.20.Fm Received: July 20, 2015Accepted:
May 27, 2015
DOI:
10.3367/UFNr.0185.201510l.1089