Regensburg 2016 – scientific programme

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MA: Fachverband Magnetismus

MA 38: Multiferroics I (DF with MA)

MA 38.6: Talk

Thursday, March 10, 2016, 11:30–11:50, H25

Kibble-Zurek mechanism in hexagonal RMnO₃ — •Quintin Meier¹, Andres Cano², and Nicola Spaldin¹ — ¹ETH Zürich, Department for Materials Theory, Zürich, Switzerland — ²CNRS, Université de Bordeaux, ICMCB, UPR 9048, 33600 Pessac, France

We present a theoretical study of the effect of cooling rate on the ferroelectric domain formation in the multiferroic hexagonal manganites, RMnO3 (R is Y or a small rare-earth atom). The hexagonal manganites are of interest because of their unusual improper ferroelectricity, which allows multiferroism and promotes conducting domain walls. In addition, the associated structural phase transition has recently been shown to form topological defects according to the Kibble-Zurek scaling law [1], which describes the number of topological defects formed as a function of cooling rate. Here we investigate the Kibble-Zurek scaling for a range of compounds in the RMnO3 series by using first principles density functional theory to calculate trends in the scaling parameters. We present possible models that describe the experimentally observed deviations from Kibble-Zurek scaling at both very fast and very slow cooling rates.

[1] Griffin, S. M., Lilienblum, M., Delaney, K. T., Kumagai, Y., Fiebig, M., & Spaldin, N. A. (2012) Physical Review X, 2(4), 041022.