Electrocaloric effects in the lead-free Ba(Zr,Ti)O3 relaxor ferroelectric from atomistic simulations

Abstract

Atomistic effective Hamiltonian simulations are used to investigate electrocaloric (EC) effects in the lead-free Ba(Zr0.5Ti0.5)O3 (BZT) relaxor ferroelectric. We find that the EC coefficient varies non-monotonically with the field at any temperature, presenting a maximum that can be traced back to the behavior of BZT's polar nanoregions. We also introduce a simple Landau-based model that reproduces the EC behavior of BZT as a function of field and temperature, and which is directly applicable to other compounds. Finally, we confirm that, for low temperatures (i.e., in non-ergodic conditions), the usual indirect approach to measure the EC response provides an estimate that differs quantitatively from a direct evaluation of the field-induced temperature change.

Local Structural Heterogeneity and Electromechanical Responses of Ferroelectrics: Learning from Relaxor Ferroelectrics

“…Solid Solution Relaxors that Combine Ferroelectric and Paraelectric End‐Members : A typical example of this type of relaxors is BaZrO 3 ‐BaTiO 3 (BZT) . For the BZT system, BT is a ferroelectric material at room temperature while BZ is in paraelectric phase.…”

Mechanisms of Pyroelectricity in Three- and Two-Dimensional Materials

“…wurtzite zinc oxide ZnO) are emerging as promising alternative candidates for pyroelectric devices 9,13 as they do not have a Curie temperature above which the pyroelectric behavior vanishes. The converse of the pyroelectric effect, the electrocaloric effect, has also attracted intensive interest [14][15][16][17][18][19][20] . Despite these extensive applications, the theory of the pyroelectric effect has not received due attention and, as a result, adequate understanding of the microscopic mechanisms that control the effect is still lacking.…”

Designing coexisting multi-phases in PZT multilayer thin films: an effective way to induce large electrocaloric effect

“…[1][2][3][4][5] Electrocaloric effect (ECE) is considered to be one of the most important thermodynamic effects employed in refrigeration technologies. 6,7 Electrocaloric materials, such as inorganic ferroelectrics, [8][9][10] relaxor ferroelectrics, 11,12 and organic polymer lms, 13,14 have been widely studied. The electrocaloric effect is a change in the temperature (DT) of a ferroelectric (FE) material by the change in entropy (DS) upon the application or withdrawal of an electric eld under adiabatic conditions.…”