Dynamic magnetoelectric phenomena within electromagnons in rare-earth borate multiferroics

A.A. Mukhin^a, A.M. Kuzmenko^a, V.Yu. Ivanov^a, A.G. Pimenov^b, A.M. Shuvaev^b, V.E. Dziom^b
^aProkhorov General Physics Institute of the Russian Academy of Sciences, ul. Vavilova 38, Moscow, 119991, Russian Federation
^bInstitute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstraße 8-10, Vienna, 1040, Austria

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 H_b → −H_b. 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.

Keywords: magnetoelectric phenomena, multiferroics, magnetic excitations, magnetic spectroscopy, antiferromagnetic resonance
PACS: 75.85.+t, 76.50.+g, 78.20.Fm (all)
DOI: 10.3367/UFNe.0185.201510l.1089
URL: https://ufn.ru/en/articles/2015/10/g/
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000367246700006
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2-s2.0-84954315043
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2015PhyU...58..993M
Citation: Mukhin A A, Kuzmenko A M, Ivanov V Yu, Pimenov A G, Shuvaev A M, Dziom V E "Dynamic magnetoelectric phenomena within electromagnons in rare-earth borate multiferroics" Phys. Usp. 58 993–1001 (2015)

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Received: 20th, July 2015, accepted: 27th, May 2015

Оригинал: Мухин А А, Кузьменко А М, Иванов В Ю, Пименов А Г, Шуваев А М, Дём В Е «Динамические магнитоэлектрические явления в области электромагнонов в мультиферроиках на основе редкоземельных боратов» УФН 185 1089–1098 (2015); DOI: 10.3367/UFNr.0185.201510l.1089