Electro-caloric behaviors of lead-free Bi0.5Na0.5TiO3-BaTiO3 ceramics

Zheng, Xinliang; Zheng, Gengfeng; Lin, Zheng; Jiang, Zhiyuan

doi:10.1007/s10832-011-9673-4

Cited by 60 publications

(19 citation statements)

References 12 publications

(16 reference statements)

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“…The obtained results of direct ECE measurements in NBT are in deep contrast to the published results obtained using the indirect ECE determining method [5,7,8,14]. The negative T of NBT, obtained by measurements of bipolar polarization hysteresis loops in the ferroelectric state and by applying of the Maxwell relation, can be explained by the increased resistance of domain reorientation to the change of the electric field if the temperature is lowered [9,25,47].…”

Section: Resultscontrasting

confidence: 71%

“…(3)) can be used in the interpretation of P(T) E=const , obtained from polarization hysteresis loops. This contribution is remarkable in case if E max does not exceed E coerc much [7,8,14] or in case of inclined polarization hysteresis loops with weakly expressed saturation [5]. In both cases a completely poled state is not achieved and P rem depends on E max .…”

Section: Resultsmentioning

confidence: 99%

“…Na 0.5 Bi 0.5 TiO 3 (NBT) -based compositions in the concentration region of rhombohedral phase and the morphotropic phase boundary (MPB), which are widely studied due to promising piezoelectric properties, have been recently considered also with respect to ECE [5][6][7][8][9][10][11][12][13][14][15][16][17]. Except for [11,17], all studies based on the indirect measurements of ECE revealed temperature regions with remarkable so-called negative ECE -decreasing of temperature if the electric field is applied and increasing of temperature if the electric field is removed.…”

Section: Introductionmentioning

confidence: 99%

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Direct and indirect determination of electrocaloric effect in Na0.5Bi0.5TiO3

Birks

Dunce

Peräntie

et al. 2017

Journal of Applied Physics

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Direct and indirect studies of electrocaloric effect were performed in poled and depoled Na 0.5 Bi 0.5 TiO 3 . For this purpose polarization and electrocaloric effect temperature change measurements were made at different electric field pulses as a function of temperature. Applicability of the widely-used indirect electrocaloric effect determination method, using the Maxwell relation, was critically analyzed with respect to the reliable direct measurements.Quantitative differences were observed between the results obtained by both approaches in case of the poled Na 0.5 Bi 0.5 TiO 3 sample. These differences can be explained by the temperature-dependent concentration of domains oriented in the direction of the applied electric field. Whereas in the depoled Na 0.5 Bi 0.5 TiO 3 , which is characterized by electric field dependence of polar nanoregions embedded in a nonpolar matrix, the Maxwell relation is not applicable at all, as it is indicated by the obtained results. Possible mechanisms which could be responsible for the electrocaloric effect in the relaxor state were considered. The results of this study are used to evaluate the numerous results obtained and published by other authors, using the Maxwell relation to indirectly determine electrocaloric effect. The reason of the negative electrocaloric effect values, obtained in such a way and widely discussed in literature in case of Na 0.5 Bi 0.5 TiO 3 , have been explained in this study.

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Section: Resultscontrasting

confidence: 71%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Direct and indirect determination of electrocaloric effect in Na0.5Bi0.5TiO3

Birks

Dunce

Peräntie

et al. 2017

Journal of Applied Physics

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“…[3][4][5][6][7][8][9][10] On the other hand, Bai et al 2 reported the observation of a negative ECE for the first time in Bi 1/2 Na 1/2 TiO 3 -BaTiO 3 solid solution at temperature ranging from 25 to 145 C. Zheng et al 8 have observed the coexistence of a positive and negative ECE as well as the reversal of the sign of ECE above 160 C in the morphotropic-phase-boundary (MPB) composition 0.94(Bi 1/2 Na 1/2 TiO 3 )-0.06BaTiO 3 (0.94BNT-0.06BT) which can adversely affect the operation of a cooling system at high temperatures. A similar coexistence of a positive and negative ECE was also observed via both direct and indirect measurement techniques by Goupil et al 11 in the Pb 1/3 Mg 2/3 O 3 -30PbTiO 3 single crystals.…”

Section: Introductionmentioning

confidence: 99%

Unification of the negative electrocaloric effect in Bi1/2Na1/2TiO3-BaTiO3 solid solutions by Ba1/2Sr1/2TiO3 doping

Uddin

Zheng

Iqbal

et al. 2013

Journal of Applied Physics

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The microscopic mechanisms of the negative electrocaloric effect (ECE) of the single-phase (1Àx)(0.94Bi 1/2 Na 1/2 TiO 3 -0.06BaTiO 3 )-xBa 1/2 Sr 1/2 TiO 3 (BNT-BT-BST) perovskite solid solutions fabricated via the sol-gel technique are explored in this study. Dielectric and mechanical relaxation analyses are employed to investigate the ferroelectric and structural transitions of the samples. The electrocaloric properties of the samples were measured by thermodynamics Maxwell relations. The difference between the depolarization temperature (T d ) and the maximum dielectric constant temperature (T m ) was found to decrease with increasing BST content. Doping with BST stabilized the ferroelectric phase along with unifying the EC temperature changes (DT) to only negative values. The origin of the uniform negative ECE of BNT-BT-BST is discussed. V C 2013 AIP Publishing LLC. [http://dx

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“…Between 2008 and 2014, the group at the University of Barcelona published three papers on the EsCE of single-crystalline Cu 68 Zn 16 Al 16 , where they measured a negative adiabatic temperature change of about 6 K in the temperature range between 200 and 350 K [105], estimated it to 15 K using the Clausius-Clapeyron relation [106], as well as analysing the homogeneity of the EsCE distribution along the sample [107]. In 2012, Cui et al [108] presented the EsCE on polycrystalline Ni-Ti wires.…”

Section: Elastocaloric Materialsmentioning

confidence: 99%

Alternative Caloric Energy Conversions

Kitanovski

Tušek

Tomc

et al. 2014

Magnetocaloric Energy Conversion

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In this chapter, some alternative, "ferroic", solid-state energy conversion technologies are presented. These are the electrocaloric (pyroelectric), the barocaloric and the elastocaloric energy conversions. In their nature, they are analogous to magnetocaloric energy conversion; however, different external influences are needed to initialize the caloric effect. In the case of electrocaloric energy conversion, this is related to a change in the electric field; in the case of barocalorics, to a change in the hydrostatic pressure and in the case of elastocaloric energy conversion, to a change in the mechanical stress. Each group, to some extent, possesses possible advantages as well as some disadvantages in comparison with magnetocaloric energy conversion. However, since all three alternative solid-state energy conversion technologies are at an early stage of development, it is not yet reasonable to compare them with magnetocaloric energy conversion. It is only time and further research that will show the full potential of these alternative solid-state energy conversion technologies.This chapter is divided into three sections. In each section, the physical principle behind the discussed ferroic effect will be presented and an overview of existing materials with their physical properties will be made. Furthermore, different possibilities for designing an energy conversion device using these materials will be reviewed (especially for electrocalorics). However, since the technology based on these three effects is at an early stage of development, only a few prototypes of energy conversion devices have been presented. Electrocaloric and Pyroelectric Energy ConversionIn this subsection, the electrocaloric and pyroelectric energy conversions are presented and discussed. In general, the electrocaloric energy conversion stands for the heat pumping processes (or refrigeration), whereas the pyroelectric energy conversion stands for the power generation.The underlying mechanism of the electrocaloric energy conversion is the so-called electrocaloric effect. The electrocaloric effect is expressed as the temperature change of dielectric materials subjected to a varying electric field. To simplify, as the electrocaloric material is subjected to a positive electric field change the material heats up, yet as the electric field is turned off the opposite occurs and the material cools down. Speaking thermodynamically, the electrocaloric effect is analogue to the magnetocaloric effect, though instead of the magnetic field change an electric field change is required to induce the caloric effect in the material. However, the electrocaloric energy conversion has some potential advantages over the magnetocaloric energy conversion, such as higher power density and higher compactness of the energy conversion devices, no dependence on rare-earth materials, no moving parts of the device, operation of the devices with less vibrations, silent operation, etc. Nevertheless, the area of the electrocaloric energy conversion only recently attracted m...

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Electro-caloric behaviors of lead-free Bi0.5Na0.5TiO3-BaTiO3 ceramics

Cited by 60 publications

References 12 publications

Direct and indirect determination of electrocaloric effect in Na0.5Bi0.5TiO3

Direct and indirect determination of electrocaloric effect in Na0.5Bi0.5TiO3

Unification of the negative electrocaloric effect in Bi1/2Na1/2TiO3-BaTiO3 solid solutions by Ba1/2Sr1/2TiO3 doping

Alternative Caloric Energy Conversions

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