Dresden 2014 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 20: Nonlinear dielectics, phase transitions, relaxors

DF 20.2: Vortrag

Donnerstag, 3. April 2014, 10:50–11:10, GER 37

Tuning of the electrocaloric effect in BaTiO₃ and PbTiO₃-based relaxors by molecular dynamics simulations — •Anna Grünebohm¹, Peter Entel¹, Takeshi Nishimatsu², and Scott P. Beckman³ — ¹Faculty of Physics and CENIDE, University of Duisburg-Essen, 47048 Duisburg, Germany — ²Institute for Materials Research (IMR), Tohoku University, Sendai 980-8577, Japan — ³Department of Materials Science and Engineering, Iowa State University, Ames, IA 50011, United States

The electrocaloric effect is an adiabatic temperature change of a material upon applying an external electrical field. Recently, this effect has been rediscovered as a promising candidate for solid state refrigeration as large temperature changes have been found in experiment and theoretical simulations.¹⁻³ However, the underlaying mechanisms for the large caloric response as well as possible obstacles are still not well understood. In addition, the effective temperature range in pure ferrolectric materials is narrow. We thus perform molecular dynamics simulations of an ab-initio based effective Hamiltonian as implemented in the feram package³ in order to study the effect of local fields, defects, and alloying on the electro caloric response and its operation range. Our systematic study will focus on BaTiO₃, (Ba,Sr)TiO₃, PbTiO₃ and PNM-PT.

1 A. Mishenko, et al, Science 311, 1270 (2006)

2 I. Ponomareva et al, Phys. Rev. Lett. 108, 167604 (2012)

3 T. Nishimatsu et al, J. Phys. Soc. Jpn., 82, 114605 (2013)