Preparation of BST-BZT Laminated Relaxor Ferroelectric Ceramics and Their Electrocaloric Effect

doi:10.16553/j.cnki.issn1000-985x.2025.0112

Abstract

Abstract: Lead-free relaxor ferroelectric based laminated ceramics are one of the important choices for environmentally friendly electrocaloric solid-state refrigeration devices. In this study， the x（Ba_0.65Sr_0.35）TiO₃-（1-x）Ba（Zr_0.2Ti_0.8）O₃（0.8BST-0.2BZT， x=0.8； 0.2BST-0.8BZT， x=0.2） thick films were prepared via tape-casting process， and the laminated ceramics of 0.8BST-0.2BZT/0.2BST-0.8BZT/0.8BST-0.2BZT were constructed using a stacking process. Meanwhile， 0.8BST-0.2BST and 0.2BST-0.8BZT ceramics were prepared by solid-state reaction for comparison， and their microstructure， dielectric temperature characteristics， ferroelectricity， and electrocaloric effects were studied. The research results indicate that laminated ceramics have more pronounced dielectric relaxation characteristics and larger polarization difference （P_s-P_r）. The significant electrocaloric effect （ΔT=0.9 K） and wide broad working temperature span （T_span=50 ℃） of laminated ceramics were measured using indirect measurements under an electric field of 50 kV/cm. This result is further verified by direct measurements under 25 kV/cm， and significant electrocaloric temperature change （ΔT=0.25 K） and T_span （>45 ℃） were observed. This work demonstrates that the developed laminated ceramics possess excellent temperature stability and wide temperature range adaptability， showing great potential for electrocaloric cooling applications.

Key words: relaxor ferroelectric; laminated ceramics; electrocaloric effect; working temperature span; direct measurement; indirect measurement

CLC Number:

O738

XUE Fei, TIAN Yahui, JIN Ling. Preparation of BST-BZT Laminated Relaxor Ferroelectric Ceramics and Their Electrocaloric Effect[J]. Journal of Synthetic Crystals, 2026, 55(1): 93-102.

Figures/Tables 9

Fig.1 Schematic diagram of research design

Fig.2 Fabrication process flow chart （a）， sintering curve （b） and finished product image （c） of laminated ceramics

Fig.3 XRD patterns of BST-BZT ceramics （a）， Rietveld refinement plots of 0.8BST-0.2BZT （b） and 0.2BST-0.8BZT （c） ceramics

Fig.4 Microstructure and composition analysis of laminated ceramic cross-section. （a） ×5 000 times；（b） ×500 times；（c） SEM images of 0.8BST-0.2BZT cross-section for thermal corrosion；（d） SEM images of 0.2BST-0.8BZT cross-section for thermal corrosion；（e）~（h） EDS point analysis spectra （corresponding to points A~D）；（i） EDS line scan spectra in the thickness direction of the laminated ceramics

Fig.5 Dielectric permittivity-temperature and diffusive properties of samples. （a） Dielectric permittivity-temperature spectra；（b） Curie-Weiss law fitting；（c） comparison of H-W2/3-m peak width；（d） Gaussian fitting of diffuse phase transition temperature；（e） comparison of diffuse phase transition temperatures

Fig.6 Ferroelectric properties of samples. （a） P-E hysteresis loops；（b） comparison of polarization properties；（c） coercive field；（d） I-V characteristic curves

Fig.7 Temperature-dependent P-E hysteresis loops of 0.8BST-0.2BZT （a）， 0.2BST-0.8BZT （b）， laminated ceramics （c） under an electric field of 50 kV/cm；（d） ΔT versus temperature curves obtained by indirect measurement method

Fig.8 Electrocaloric temperature change of BZT-BST ceramics measured by directly method

Fig.9 Comparative study of directly measured electrocaloric effects in different ferroelectric ceramic systems

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