Giant electrocaloric effect in BaZr0.2Ti0.8O3 thick film

Ye, Hui Jian; Qian, Xiao Shi; Jeong, Dae‐Yong; Zhang, Shujun; Zhou, Yue; Shao, Wen; Zhen, Liang; Zhang, Q. M.

doi:10.1063/1.4898599

Cited by 91 publications

(52 citation statements)

References 30 publications

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“…One may therefore wonder about EC effects in lead-free relaxor ferroelectrics, even more when realizing that a recent study done in Ba(Zr 1−x Ti x )O 3 with x = 0.20 reported a giant α electrocaloric coefficient [42,43] (note that this system is different from Ba(Zr 0.5 Ti 0.5 )O 3 in the sense that it possesses a polar ground state in addition to some relaxor features). For instance, many questions remain to be addressed in Ba(Zr 0.5 Ti 0.5 )O 3 : Do indirect and direct methods also provide different results below a specific temperature?…”

Section: ∂T ∂E Smentioning

confidence: 99%

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

et al. 2017

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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.

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Section: ∂T ∂E Smentioning

confidence: 99%

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

et al. 2017

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“…17 Such electrocaloric effect can be further enhanced in thick film form. 45 The phase transition temperature where the maximum electrocaloric response occurs can be tailored by varying the doping level 16,17 without destroying the multiphase coexistence 45 or through solid solutions. 46 Such approach is therefore efficient for tuning the working temperature and improving electrocaloric responses of materials.…”

Section: 3mentioning

confidence: 99%

Some strategies for improving caloric responses with ferroelectrics

2016

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Many important breakthroughs and significant engineering developments have been achieved during the past two decades in the field of caloric materials. In this review, we address ferroelectrics emerging as ideal materials which permit both giant elastocaloric and/or electrocaloric responses near room temperature. We summarize recent strategies for improving caloric responses using geometrical optimization, maximizing the number of coexisting phases, combining positive and negative caloric responses, introducing extra degree of freedom like mechanical stress/pressure, and multicaloric effect driven by either single stimulus or multiple stimuli. This review highlights the promising perspective of ferroelectrics for developing next-generation solid-state refrigeration.

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“…Since a giant ECE of ∆T max = 12K was obtained in PbZr 0.95 Ti 0.05 O 3 thin film in 2006 [1], the researches on ECE boom in various ferroelectric ceramics [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. However, large amount of high power devices working in a small space will induce local high temperature, which degrades the performance of electronic devices and may even lead to complete failure.…”

Section: Introductionmentioning

confidence: 99%

“…The substitution of Zr 4+ on Ti 4+ also diffuses the phase transition and results in a high ∆T in a broad temperature range [12,13]. The substitution of Sn 4+ on Ti 4+ leads to a 4 microscope (SEM, JSM-6510A).…”

Section: Introductionmentioning

confidence: 99%

Effect of donor doping in B sites on the electrocaloric effect of BaTi_1−xNb_xO₃ ceramics

Bai

Han

2015

RSC Adv.

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This paper demonstrates the effect of donor doping in B sites on the electrocaloric effect (ECE) in BaTi 1-x Nb x O 3 (x=0~0.01) ferroelectric ceramics. The Nb substitution on Ti does not affect the formation of perovskite structure, while it obviously inhabits the grain growth in sintering process. The donor doping of Nb controls the ferroelectric phase transition more efficiently than the equivalent substitutions either in A or B sites. It lowers the phase transition temperature aboutone order of magnitude faster than the equivalent substitution, so that the ECE ∆ ∆ ∆ ∆T max shifts accordingly. Nb doping also diffuses the phase transition, so that the ECE ∆ ∆ ∆ ∆T max reduces and the peak becomes much wider. Compared with BaTiO 3 , ∆ ∆ ∆ ∆T max of BaTi 0.994 Nb 0.006 O 3 drops one third, while the full width at half maximum increases twice, indicating a better refrigeration capacity. a Corresponding author. 3 high ∆T at morphotropic phase boundary [14,15]. In addition, the co-substitution of Ca 2+ on Ba 2+ and Zr 4+ on Ti 4+ was also studied [16-21]. Up to now, all reports focused on the effect of various equivalent dopings but the inequivalent doping has not been researched for ECE, although the inequivalent dopings were reported to improve the dielectric and piezoelectric properties more efficiently [22,23]. The donor doping of Nb 5+ on Ti 4+ in B sites, a typical soft doping, has a notable effect on modifying the ferroelectric phase transition. This paper reports its effects on the phase composition, microstructure, dielectric, ferroelectric and electrocaloric effects of BaTiO 3 ceramics,and a better refrigeration capacity is obtained. Experimental procedure Sample preparationThe BaTi 1-x Nb x O 3 (x=0~0.01) ceramics were prepared by the conventional solid-state reaction method. Analytical reagent grade BaCO 3 , TiO 2 and Nb 2 O 5 were used as raw materials. After the mixed powders were calcined at 1000 °C, they were grinded by planetary ball mill. The resultant powders were dry-pressed in a stainless-steel die under a pressure of 3 MPa and the pressed pellets were sintered at 1350 °C for 4 hours in air. CharacterizationThe phase composition of calcined powders were characterized by X-ray diffraction (XRD) using Cu K α radiation (λ=0.15418 nm) with a scanning rate of 2 °/min. The microstructure of the sintered samples was observed by scanning electron (Figure 2(a)), Nb doped samples exhibit obviously small grain size, less than 1µm, which further decreases with increasing Nb amount (Figure 2 (b)~(d)). It is because the donor doping of Nb accumulates at grain boundaries, which hinders the motion of grain boundaries during the sintering process. The densities of all sintered samples are larger than 5.92 g/cm 3 , i.e. 98% of theoretical density, which well agrees with the SEM observations. Thermal analysisThe thermal characters of tetragonal-cubic (T-C) phase transition are shown in the heat flow curves in Figure 3. With the rise of Nb amount, the endothermic peak gradually moves to lower temperature, indicatin...

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Giant electrocaloric effect in BaZr0.2Ti0.8O3 thick film

Cited by 91 publications

References 30 publications

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

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

Some strategies for improving caloric responses with ferroelectrics

Effect of donor doping in B sites on the electrocaloric effect of BaTi_1−xNb_xO₃ ceramics

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Giant electrocaloric effect in BaZr0.2Ti0.8O3 thick film

Cited by 91 publications

References 30 publications

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

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

Some strategies for improving caloric responses with ferroelectrics

Effect of donor doping in B sites on the electrocaloric effect of BaTi1−xNbxO3 ceramics

Contact Info

Product

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Effect of donor doping in B sites on the electrocaloric effect of BaTi_1−xNb_xO₃ ceramics