BaZr0.2Ti0.8O3陶瓷的热波热释电探测
Pyroelectric thermo-wave probing of BaZr0.2Ti0.8O3 ceramics
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中文总结 AI 辅助
本研究通过热波热释电探测固相合成的BaZr0.2Ti0.8O3陶瓷，发现其极性态存在不对称热释电响应，并揭示非遍历弛豫态及铁电-弛豫共存特性。
中文摘要 AI 辅助
BaxZr1-xTiO3陶瓷（0.15 < x < 0.25）具有高介电常数、小漏电流和低损耗因子，是用于可调电容器件、多层陶瓷电容器和压电致动器的有前景材料。这些材料因Ti4+离子被离子半径更大的Zr4+离子等价取代而产生的局部化学应变而表现出弛豫体特性。然而，据我们所知，x~0.2的BaxZr1-xTiO3陶瓷的热释电性能尚未被研究。为填补这一知识空白，我们对通过固相合成制备的BaZr0.2Ti0.8O3陶瓷进行了热波热释电探测。对最有趣的极性态（即极化态、去极化态、弛豫态和恢复极化态）的热波探测结果显示，存在显著的热释电响应，该响应相对于陶瓷的两个相对表面可能呈现强烈不对称性。热释电响应的不对称性和分布显著依赖于电场循环的历史，表明陶瓷样品中可能存在非遍历性弛豫型极性态。在室温下记录的X射线衍射谱显示，宏观四方性几乎不存在，且(200)峰具有弱不对称性，这表明富钛极性纳米区域内存在较小的四方性。加热过程中714 cm-1处拉曼带的相对强度降低，证明了在30°C至40°C之间存在弥散的铁电-顺电相变。介电常数的温度依赖性遵循修正的居里-外斯定律，指数为1.4，表明有序铁电态和弛豫态共存于BaTi0.8Zr0.2O3陶瓷中。
英文摘要
BaxZr1-xTiO3 ceramics with 0.15 < x < 0.25, which have high dielectric permittivity, small leakage currents and low dissipation factor, are promising materials for tunable capacitor devices, multilayered ceramic capacitors and piezoelectric actuators. These materials reveal relaxor properties due to the local chemical strains caused by the isovalent substitution of Ti4+ ions by Zr4+ ions with a larger ionic size. However, to the best of our knowledge, the pyroelectric properties of BaxZr1-xTiO3 ceramics with x~0.2 have not been studied. To fill the gap in knowledge, we perform the pyroelectric thermo-wave probing of BaZr0.2Ti0.8O3 ceramics prepared by the solid-state synthesis. Results of the thermo-wave probing of the most interesting polar states, namely polarized, depolarized, relaxed and restored polarized states, reveal the pronounced pyroelectric response that can be strongly asymmetric with respect to the opposite surfaces of the ceramics. The asymmetry and profiles of pyroelectric response depend significantly on the pre-history of the electric field cycling indicating possible non-ergodic relaxor-type polar states in the ceramic sample. X-ray diffraction spectrum, recorded at room temperature, reveals the virtual absence of the macroscopic tetragonality and the weak asymmetry of the (200) peak, which indicate the small tetragonality inside the Ti-enriched polar nanoregions. Decrease of the relative intensity of the Raman band at 714 cm-1 occurring upon heating evidences the diffuse ferroelectric-paraelectric phase transition between 30 C and 40 C. The temperature dependence of the dielectric permittivity obeys modified Curie-Weiss law with power 1.4, indicating that both ordered ferroelectric and relaxor states coexist in the BaTi0.8Zr0.2O3 ceramics.Results can be useful for elaboration of lead-free relaxor ferroelectric ceramics for advanced pyroelectric applications.
发表机构
- Institute of Physics, National Academy of Sciences of Ukraine（乌克兰国家科学院物理研究所）
- Frantsevich Institute for Problems in Materials Science, National Academy of Sciences of Ukraine（乌克兰国家科学院弗兰采维奇材料科学问题研究所）
- V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine（乌克兰国家科学院瓦·拉沙卡罗夫半导体物理研究所）
- Institute of Physics, Czech Academy of Sciences（捷克科学院物理研究所）
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