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Interplay of structural distortions, dielectric effects and magnetic order in multiferroic GdMnO3

Doerr, Mathias and Loewenhaupt, Michael and Wagh, Aditya A and Kumar, Anil PS and Elizabeth, Suja and Roessler, Sahana and Rotter, Martin and Wirth, Steffen (2013) Interplay of structural distortions, dielectric effects and magnetic order in multiferroic GdMnO3. In: Journal of the Korean Physical Society, 62 (10). pp. 1449-1452.

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Official URL: http://dx.doi.org/

Abstract

Multiferroic materials are characterized by simultaneous magnetic and ferroelectric ordering making them good candidates for magneto-electrical applications. We conducted thermal expansion and magnetostriction measurements in magnetic fields up to 14 T on perovskitic GdMnO3 by highresolution capacitive dilatometry in an effort to determine all longitudinal and transversal components of the magnetostriction tensor. Below the ordering temperature T (N) = 42 K, i.e., within the different complex (incommensurate or complex) antiferromagnetic phases, lattice distortions of up to 100 ppm have been found. Although no change of the lattice symmetry occurs, the measurements reveal strong magneto-structural phenomena, especially in the incommensurate sinusoidal antiferromagnetic phase. A strong anisotropy of the magnetoelastic properties was found, in good agreement with the type and propagation vector of the magnetic structure. We demonstrate that our capacitive dilatometry can detect lattice expansion effects and changes of the dielectric permittivity simultaneously because the sample is housed inside the capacitor. A separation of both effects is possible by shielding the sample. Dielectric transitions could be detected by this method and compared to the critical values of H and T in the magnetic phase diagram. Dielectric changes measured at 1 kHz excitation frequency are detected in GdMnO3 at about 180 K, and between 10 K and 25 K in the canted antiferromagnetic structure which is characterized by a complex magnetic order on both the Gd- and Mn-sites.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to Korean Physical Society.
Keywords: Manganites; Magnetostriction; Dielectric Properties; Dilatometry
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Depositing User: Francis Jayakanth
Date Deposited: 06 Aug 2013 11:39
Last Modified: 06 Aug 2013 11:39
URI: http://eprints.iisc.ac.in/id/eprint/46918

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