Strain coupling in multiferroic phase transitions of samarium yttrium manganite Sm_{0.6}Y_{0.4}MnO_{3}

Schiemer, Jason and O’Flynn, Daniel and Balakrishnan, Geetha and Carpenter, Michael A. (2013) Strain coupling in multiferroic phase transitions of samarium yttrium manganite Sm_{0.6}Y_{0.4}MnO_{3}. Physical Review B, 88 (5). 054108. ISSN 1098-0121, ESSN: 1550-235X DOI 10.1103/PhysRevB.88.054108

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Abstract

Sm1−xYxMnO3 (SYM x) is one of a class of multiferroic manganites that has seen significant recent interest due to the intimate connection between cycloidal magnetic order and ferroelectricity in these materials. SYM shows sequential transitions between paramagnetic, sinusoidally ordered antiferromagnetic and cycloidally ordered antiferromagnetic phases with decreasing temperature. As in the other members of the family, the magnetic spin cycloid induces ferroelectricity, although whether there is any elastic coupling involved in this process is not known. In this work, resonant ultrasound spectroscopy (RUS) is used to examine the stiffness and dissipation in SYM 0.4 as the magnetic transitions are traversed. It is found that there are only very small signatures of the transitions in the elastic properties of the material, indicating the weakness of the magnetoelastic (and electroelastic) coupling. The mechanical loss does show a significant decrease upon cooling below TN1=∼50 K, indicating the freezing of some loss mechanism near the temperature where magnetic order is achieved. The strain at these magnetic transitions in a related material, Eu1−xYxMnO3, is examined from data published in the literature, and very low shear strain is observed, along with a more significant volume strain effect. This correlates well with the observations from RUS, as the peak frequencies are more sensitive to shear effects than bulk effects. These results suggest that the weak coupling of the magnetic transitions with shear may be a more general behavior in multiferroic perovskite-related manganites.

Item Type: Article
Uncontrolled Keywords: 2013AREP; IA66;
Subjects: 03 - Mineral Sciences
Divisions: 03 - Mineral Sciences
Journal or Publication Title: Physical Review B
Volume: 88
Page Range: 054108
Identification Number: 10.1103/PhysRevB.88.054108
Depositing User: Sarah Humbert
Date Deposited: 09 Nov 2013 16:06
Last Modified: 15 Nov 2013 14:25
URI: http://eprints.esc.cam.ac.uk/id/eprint/2904

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