| 학회 |
한국재료학회 |
| 학술대회 |
2017년 봄 (05/17 ~ 05/19, 목포 현대호텔) |
| 권호 |
23권 1호 |
| 발표분야 |
1. 고에너지 밀도 및 전기열량 유전체(High Energy Density and Electrocaloric Materials) |
| 제목 |
Phase Transition Behavior and Electrocaloric Effect in BaTiO3-Bi(Zn,Ti)O3 Ceramics |
| 초록 |
Relaxor ferroelectrics have been applied to many electronic devices due to their giant dielectric and electromechanical responses. Recently, they attract great attention due to its high electro-caloric effect (ECE) which is change of entropy and temperature by electric field. Pb(Mg,Nb)O3-PbTiO3 (PMN-PT) is one of the mostly investigated relaxor ferroelectrics. A global environment issue demands lead-free relaxor ferroelectrics. Solid solutions between BaTiO3 and Bi-based perovskites such as BiFeO3, BiScO3 and Bi(Zn,Ti)O3 have been reported to show pseudo-cubic phases in intermediate composition regions which have overall cubic structure with polar nanoregions (PNR) and are expected to show high ECE. The Bi-based perovskite-barium titanate solid solution with a BT-rich composition could be a good candidate for solid state cooling device using ECE because their transition temperatures are higher than room temperature by a few tens of degrees. In this work, phase transition behavior and ECE were investigated in solid solutions between Bi(Zn,Ti)O3 (BZT) and BaTiO3. Samples were prepared by conventional ceramic process. The crystal structure changed from tetragonal to pseudo-cubic around 0.05BZT-0.95BT when the amount of BZT increased. The temperature dependence of permittivity showed that the phase transition behavior also changed from ferroelectric to relaxor around 0.95BT. Polarization-electric field (P-E) hysteresis curves were measured at temperatures of RT ~ 180oC in BZT-BT ceramics with compositions near 0.95BT and temperature changes due to ECE were calculated indirectly with temperature dependences of polarizations using Maxwell relation. |
| 저자 |
김대수, 김빛찬, 김정석, 천채일
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| 소속 |
호서대 |
| 키워드 |
Electrocaloric Effect; ferroelectric; relaxor; BaTiO<SUB>3</SUB>-Bi(Zn; Ti)O<SUB>3</SUB>
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| E-Mail |
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