The giant electrocaloric effect in EuTiO3 nanowires near room temperature

Wang, Xinyu; Rui-Jiang, Chu; Dong, Zhengchao; Zhong, Chonggui; Yao, Min; Wang, M.; Zhou, Peng; Yuan, Guoliang; Sheng-Nan, Wei

doi:10.1016/j.jallcom.2015.07.069

Cited by 8 publications

(5 citation statements)

References 42 publications

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“…Based on the thermodynamic calculations and phase‐field simulations, the outstanding ECE performance is resulting from the size effects of nanowire. It has been studied from both experimental and theoretical approaches, but still less understood …”

Section: Introductionmentioning

confidence: 99%

Size effects of electrocaloric cooling in ferroelectric nanowires

Huang

Zhang

et al. 2017

J Am Ceram Soc

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Considering finite size effect, ferroelectric nanowires may show novel phenomena compared to ferroelectric thin film and bulk. Here we investigated the effect of width and surface compressive stress on electrocaloric cooling in ferroelectric nanowire by using thermodynamic calculations and phase-field simulations. It was found that the isothermal entropy change and adiabatic temperature change in nanowire are 50% larger than that in thin film due to different mechanical boundary conditions of nanowire and thin film. The largest electrocaloric temperature changes were shown to increase significantly either with the decrease in nanowire width or the increase with the surface compressive stress. It was also revealed that the largest intrinsic entropy changes are almost the same for different nanowires with different widths and various stresses. The present study therefore contributes to the understanding of size effects of electrocaloric cooling and provides guidance for experiments to design high-efficiency cooling devices using ferroelectric nanosystems. K E Y W O R D S electrocaloric effect, ferroelectric nanowire, nanosize effects, phase-field simulation, thermodynamic calculation

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Section: Introductionmentioning

confidence: 99%

Size effects of electrocaloric cooling in ferroelectric nanowires

Huang

Zhang

et al. 2017

J Am Ceram Soc

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“…达到15 K [21] ; 垂直分布PTO纳米线在1306 kV/cm 下最大ΔT获得也仅12.5 K [11] . 中, 通过应力的施加也能呈现相同规律 [20] . 可见施加不同取向的外应力都能改变其相变温度, 但由于表面应力对平行分布纳米线弹性能的影响更加显著, 系统能量变化更为剧烈, 且畴变不再是单一的单畴到多畴的转变, 而是在不同拉压应力下呈现出的多种畴变形式, 因此能获得更大的ΔT的变化.…”

Section: 结果与讨论unclassified

Simulation of surface stress and solid solution modification phase field of nanowire electrocaloric effect

Zou,

Zhu,

Fang

2024

Acta Phys. Sin.

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Composite films with ferroelectric nanowires as fillers exhibit high adiabatic temperature change to meet the demand of solid-state refrigeration, and their parallel-distributed filled nanowires are considered to be the key factor because of the different orientation from that of the conventional perpendicular distribution. However, the intrinsic mechanism of the electrocaloric effect of nanowires distributed in parallel is not well understood. In this paper, a parallel-distributed PbTiO<sub>3</sub> nanowire model is established to investigate the effects of surface stress and solid solution modification on their electrocaloric effects through phase field simulations. The results show that an adiabatic temperature change of 5 K can be obtained near 200 °C with 1.5% compressive stress under an electric field of 260 kV/cm. In order to further reduce its operating temperature, the electrocaloric effects of PST nanowires with different Sr contents were calculated, and it was found that the lower the doping amount of Sr the higher the phase transition temperature of PST nanowires. When the doping amount of Sr is 0.45, the phase transition temperature of the nanowires can be lowered to near 100 °C, where an adiabatic temperature change of greater than 8 K can be obtained with an electric field of 600 kV/cm. Even in the low-temperature interval from 50 to 100 °C the nanowires exhibit an adiabatic temperature change close to 8 K. The nanowires are also characterized by an adiabatic temperature change in the low-temperature interval from 50 to 100 °C. Meanwhile, in conjunction with the evolution of the simulated three-dimensional domain structure, the intrinsic mechanism of the change of the electrocaloric effect under surface stress and solid solution modification is revealed to be due to the occurrence of different types of domain switchings. Finally, the parameter combinations of components and surface stresses corresponding to the maximum value of the electrocaloric effect at different operating temperatures are discussed and analyzed. The present study provides useful theoretical guidance for the development of solid-state refrigeration based on parallel-distributed ferroelectric nanowires.

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“…Therefore, NWs with a high aspect ratio will exhibit superior ECE than the other nanomaterials such as TFs and NPs, and stress can further regulate their ECE. Dong and coworkers 101 indagated the ECE of EuTiO 3 (ETO) NWs by using the Landau thermodynamic model, they point out that the decrease in size (radius r ) and increase in external tensile stress ( σ z ) can significantly enhance its ECE. When the ETO NW with r = 1.2 nm in the external electric field to 200 MV m −1 , Δ T max reaches 15.8 K at the temperature close to 311 K. Used a phase‐field model, Zhang et al 70 .…”

Section: Intrinsic Influence Factors Of Materialsmentioning

confidence: 99%

“…In addition, the applied electric field in the abovementioned works is in the [001] direction, whereas the strain will have different effects on the ECE of ferroelectric films when the electric field is applied in different directions. Zhang et al 105 compared the EC response of STO TFs when an electric field is applied in the out-ofplane [001] direction under compressive misfit strain and in-plane [101]/[010] and [110] direction under the tensile misfit strain. It is worth noting that the effect of the applied electric field and strain on the polarization (in-plane or out-of-plane) is consistent.…”

Section: Prediction Of Thermodynamics For Eces Of Ferroelectric Thin ...mentioning

confidence: 99%

“…Therefore, NWs with a high aspect ratio will exhibit superior ECE than the other nanomaterials such as TFs and NPs, and stress can further regulate their ECE. Dong and coworkers 101 Compared with polymer nanocomposites composed of ferroelectric NPs, nanocubes (NCs), and nanorods (NRs), that of NWs show higher breakdown and EC strength, which is resulted from high aspect ratios. Subsequently, the thermodynamic and phase-field simulations were carried out to verify the excellent ECE of the as-prepared Ba 0.67 Sr 0.33 TiO 3 NW array compared to TFs, and analyzed the effect of size on dipole orientation and ECE.…”

Section: Aspect Ratio and Nanowiresmentioning

confidence: 99%

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Understanding electrocaloric cooling of ferroelectrics guided by phase‐field modeling

et al. 2022

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With the urgent need to explore low-cost, high-efficiency solid-state refrigeration technology, the electrocaloric effects of ferroelectric materials have attracted much attention in the past decades. With the development of modern computing technology, the phase-field method is widely used to simulate the evolution of microstructure at mesoscale and predict the properties of different types of ferroelectric materials. In this article, we review the recent progress of electrocaloric effects from phenomenological Landau thermodynamics theory to phase-field simulation by discussing the microcosmic composition, mesoscopic domain structures, macroscopic size/shape, and external stimulus of strain/stress. More importantly, in searching for new ferroelectric electrocaloric cooling materials, it is possible to find materials whose free energy barrier height changes rapidly with temperature, such materials have a faster change rate with polarization temperature in terms of ferroelectric macroscopic properties, from them could get superior electrocaloric effects. We compile a relatively comprehensive computational design on the high performance of electrocaloric effects in different types of ferroelectrics and offer a perspective on the computational design of electrocaloric refrigeration materials at the mesoscale microstructure level.

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The giant electrocaloric effect in EuTiO3 nanowires near room temperature

Cited by 8 publications

References 42 publications

Size effects of electrocaloric cooling in ferroelectric nanowires

Size effects of electrocaloric cooling in ferroelectric nanowires

Simulation of surface stress and solid solution modification phase field of nanowire electrocaloric effect

Understanding electrocaloric cooling of ferroelectrics guided by phase‐field modeling

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