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arXiv · 2210.04138

Origin of negative electrocaloric effect in Pnma-type antiferroelectric perovskites

Ningbo Fan·Jorge Íñiguez·L. Bellaiche·Bin Xu
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Abstract

Anomalous electrocaloric effect (ECE) with decreasing temperature upon application of an electric field is known to occur in antiferroelectrics (AFEs), and previous understanding refers to the field-induced canting of electric dipoles if there is no phase transitions. Here, we use a first-principle-based method to study the ECE in Nd-substituted BiFeO3 (BNFO) perovskite solid solutions, which has the Pnma-type AFE ground state. We demonstrate another scenario to achieve and explain anomalous ECE, emphasizing that explicit consideration of octahedral tiltings is indispensable for a correct understanding. This mechanism may be general for AFEs for which the antipolar mode is not the primary order parameter. We also find that the negative ECE can reach a large magnitude in BNFO.

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Ningbo Fan, Jorge Íñiguez, L. Bellaiche, Bin Xu. 2022-10-09. Origin of negative electrocaloric effect in Pnma-type antiferroelectric perovskites. https://doi.org/10.1103/physrevb.106.224107

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