Dresden 2014 – scientific programme
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DF: Fachverband Dielektrische Festkörper
DF 20: Nonlinear dielectics, phase transitions, relaxors
DF 20.2: Talk
Thursday, April 3, 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)