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KR: Fachgruppe Kristallographie

KR 7: Optical and Nonlinear Optical Properties II (DF jointly with KR)

KR 7.2: Talk

Wednesday, March 18, 2015, 15:20–15:40, EB 407

Influence of defects on the ferroelectric and electrocaloric properties of BaTiO₃ — •Anna Grünebohm¹ and Takeshi Nishimatsu² — ¹Fakultät für Physik, Uni Due, Germany — ²IMR, Tohoku University and Faculty of Physics, Japan

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.^1,2,3 However, the underlying mechanisms for the large caloric response as well as possible obstacles are still not well understood. In addition, the effective temperature range in pure ferroelectric 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 defects, strain, and alloying on the electrocaloric response and its operation range.
[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)