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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 7: Dielectric, Elastic and Electromechanical Properties

KFM 7.2: Vortrag

Mittwoch, 29. September 2021, 10:15–10:30, H1

Multi-step stochastic polarization reversal in orthorhombic ferroelectrics — Yuri Genenko¹, Maohua Zhang¹, •Ivan Vorotiahin¹, Ruben Khachaturyan², Yi-Xuan Liu³, Ke Wang³, and Jurij Koruza¹ — ¹Institute für Materialwissenschaft, Technische Universität Darmstadt, Darmstadt, Germany — ²Interdisciplinary Center for Advanced Materials Simulation, Ruhr-Universität Bochum, Bochum, Germany — ³State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, China

Polarization switching under applied electric fields is an important property of ferroelectrics, being crucial for the operation of the data storage FeRAM-devices and for setting up properties of piezoelectric films. Mathematical models such as KAI, NLS and IFM help understand underlying mechanisms and parameters of switching processes. Moving to structures with lower symmetries, there is a need for more complex models to describe the switching events.

A stochastic model has been developed to describe the multistep switching behaviour of a potassium sodium niobate (KNN)-based orthorhombic ceramic sample. The polarization and strain changes were measured over a large time scale and a wide range of applied electric fields. The switching paths for one-, two- and three-step processes were isolated, and the existence of coherent switching events over the multidomain structures was confirmed. The predicted and detected parameters of the processes give us a glimpse into the properties of the orthorhombic KNN materials family.