Giant caloric effects enhanced by the helix polarization at the 180° domain wall in tetragonal BaTiO<sub>3</sub>

Zhang, H; Tan, P F; Li, B; Wang, F; Wang, J B; Zhong, Xiangli; Wang, W

doi:10.1088/1361-648x/ab3d6e

Cited by 4 publications

(3 citation statements)

References 40 publications

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“…directly at the walls ∆⟨|p|⟩ x is slightly enhanced. Zhang et al [24] correlated the same observation to an enhanced caloric response. However, the opposite signs of the response on either side of the wall in combination with the small volume of this region do not allow for an overall additional cooling.…”

Section: Resultsmentioning

confidence: 74%

“…So far, additional extrinsic contributions to the temperature change by DWs have been reported at the transition between different multi-and single-domain states in strained films [16][17][18][19], in the presence of depolarization [20] or originating from complex polar vortex ordering within superlattices [21]. Furthermore, improved caloric responses coming from DWs themselves have been predicted, including positive and negative EC temperature changes at each side of the wall [22], enhancement of the adiabatic temperature change ∆T with the density and width of immobile elastic walls [23] and the enhancement of the EC on Bloch-like walls [24]. Many of these studies are based on thermodynamic models and do not answer the question of whether these local enhancements may be used in practical applications.…”

Section: Introductionmentioning

confidence: 97%

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Influence of domain walls and defects on the electrocaloric effect

2023

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The electrocaloric (EC) effect is the adiabatic temperature change of a material in a varying external electrical field which is promising for novel cooling devices. While the fundamental understanding of the caloric response of defect-free materials is well progressed, there are important gaps in knowledge on reversibility and time-stability of the response. Particularly, it is not settled how the time-dependent elements of microstructure which are always present in real materials act on the field- induced temperature changes. Ab initio based molecular dynamics simulations allow us to isolate and understand the effects arising from domain walls and defect dipoles and study their interplay. We show that domain walls in cycling fields do not improve the response in either one ferroelectric phase or at the ferroelectric phase transition but may result in irreversible heat losses. The presence of defect dipoles may be beneficial for the EC response for proper field protocols, and interestingly this benefit is not too sensitive to the defect configuration.

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Section: Resultsmentioning

confidence: 74%

Section: Introductionmentioning

confidence: 97%

Influence of domain walls and defects on the electrocaloric effect

2023

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“…In contrast to the classical Bloch-domain wall, the achiral structure maintains the symmetry of the wall, reduces the domain energy and enhances the stability of its features [35,36]. The presence of an achiral domain wall has been discovered to significantly affect the mobility of the domain wall in a PbTiO 3 thin film [37], as well as the electrocaloric effect in BaTiO3 [38]. Extensive research has been conducted on the study of the caloric impact in ferroelectric materials, specifically focusing on the electrocaloric and elastrocaloric effects.…”

Section: Introductionmentioning

confidence: 99%

Influence of Stress on the Chiral Polarization and Elastrocaloric Effect in BaTiO3 with 180° Domain Structure

Shi,

2024

Crystals

Self Cite

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The polarization and elastrocaloric effect of chiral barium titanate (BaTiO3) with an Ising–Bloch-type domain wall under stress was investigated using the Landau–Ginzburg–Devonshire (LGD) theory. It has been shown that tensile stresses increase the magnitude of the Ising polarization component in barium titanate, together with a decrease in the domain wall width. Compressive stresses cause a reduction in the Ising polarization component and an increase in the domain width. Under compressive stress, barium titanate exhibits a negative elastrocaloric effect and temperature changes with increasing stress, while BaTiO3 exhibits a positive elastrocaloric effect under tensile stress. Bloch polarization shows angle-dependent polarization under external force, but the temperature change from the elastrocaloric effect is smaller than that of Ising polarization under stress. This work contributes to the understanding of polarization evolution under tension in ferroelectrics with chiral structure.

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Significant Enhancement of Electrocaloric Effect in Ferroelectric Polycrystalline Ceramics Through Grain Boundary Barrier Engineering

Xiao,

Zhang,

Gong

et al. 2024

Adv Funct Materials

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A key challenge currently for the new ferroelectric refrigeration with high efficiency and environmental friendliness lies in the urgent demand for ferroelectric materials with huge electrocaloric effects (ECE). Ferroelectric polycrystalline ceramics with high ECE stand out as one of the most promising candidates for electrocaloric cooling applications. However, the grain boundary network, as a barrier for the cross‐transmission of charged carriers, widely exists in electrocaloric polycrystalline ceramics and is often neglected in favor of focusing more on composition regulation and structural design. Herein, a grain boundary barrier engineering is proposed that regulates the Schottky barrier at the grain boundary network in the Ba0.8Zr0.2TiO3 ceramics by a maneuverable annealing process and clarifies its critical role in enhancing the ECE of polycrystalline ceramics. As a result, a substantial enhancement of the EC performance (from 0.68 to 1.63 K at 50 °C and 80 kV cm−1, ≈2.4 times) has been achieved in the annealed Ba0.8Zr0.2TiO3 ceramics with a lower Schottky barrier. The microstructural and electrical characterization reveals that the lower Schottky barrier in the grain boundary network facilitates the domain switching and electronic transition, hence resulting in enhanced polarization response and EC performance.

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Giant caloric effects enhanced by the helix polarization at the 180° domain wall in tetragonal BaTiO₃

Cited by 4 publications

References 40 publications

Influence of domain walls and defects on the electrocaloric effect

Influence of domain walls and defects on the electrocaloric effect

Influence of Stress on the Chiral Polarization and Elastrocaloric Effect in BaTiO3 with 180° Domain Structure

Significant Enhancement of Electrocaloric Effect in Ferroelectric Polycrystalline Ceramics Through Grain Boundary Barrier Engineering

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Giant caloric effects enhanced by the helix polarization at the 180° domain wall in tetragonal BaTiO3

Cited by 4 publications

References 40 publications

Influence of domain walls and defects on the electrocaloric effect

Influence of domain walls and defects on the electrocaloric effect

Influence of Stress on the Chiral Polarization and Elastrocaloric Effect in BaTiO3 with 180° Domain Structure

Significant Enhancement of Electrocaloric Effect in Ferroelectric Polycrystalline Ceramics Through Grain Boundary Barrier Engineering

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Giant caloric effects enhanced by the helix polarization at the 180° domain wall in tetragonal BaTiO₃