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arXiv · 1505.07949

Order-disorder type critical behaviour at the magnetoelectric phase transition in multiferroic DyMnO$_3$

M. Schiebl·A. Shuvaev·Anna Pimenov·G. E. Johnstone·V. Dziom·A. A. Mukhin·V. Yu. Ivanov·A. Pimenov
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Abstract

We present the results of detailed dielectric investigations of the relaxation dynamics in DyMnO$_3$ multiferroic manganite. Strong low-frequency relaxation process near the paraelectric-ferroelectric phase transition is observed. The high frequency mode is directly to the relaxational motion of multiferroic domain walls. We provide an experimental evidence that this relaxation mode corresponds to a chirality switching of the spin cycloid in DyMnO$_3$. We demonstrate that the relaxation dynamics in DyMnO$_3$ is typical for an order-disorder phase transition and may be understood within a simple model with a double well potential. DyMnO$_3$ follows an order-disorder transition scenario implicating that a short range cycloidal order of Mn-spins exists above $T_C$. These results suggest the interpretation of the paraelectric sinusoidal phase in manganites as a dynamical equilibrium of magnetic cycloids with opposite chiralities.

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M. Schiebl, A. Shuvaev, Anna Pimenov, G. E. Johnstone, V. Dziom, A. A. Mukhin, V. Yu. Ivanov, A. Pimenov. 2015-05-29. Order-disorder type critical behaviour at the magnetoelectric phase transition in multiferroic DyMnO$_3$. https://arxiv.org/abs/1505.07949

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