Giant Piezoelectricity and High Curie Temperature in Nanostructured Alkali Niobate Lead-Free Piezoceramics through Phase Coexistence

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• 作者：Bo Wu ; Haijun Wu ; Jiagang Wu ; Dingquan Xiao ; Jianguo Zhu ; Stephen J. Pennycook
• 刊名：Journal of the American Chemical Society
• 出版年：2016
• 出版时间：November 30, 2016
• 年：2016
• 卷：138
• 期：47
• 页码：15459-15464
• 全文大小：558K
• ISSN：1520-5126

文摘

Because of growing environmental concerns, the development of lead-free piezoelectric materials with enhanced properties has become of great interest. Here, we report a giant piezoelectric coefficient (d₃₃) of 550 pC/N and a high Curie temperature (T_C) of 237 °C in (1–x–y)K_1–wNa_wNb_1–zSb_zO_3–xBiFeO_3–yBi_0.5Na_0.5ZrO₃ (KN_wNS_z-xBF-yBNZ) ceramics by optimizing x, y, z, and w. Atomic-resolution polarization mapping by Z-contrast imaging reveals the intimate coexistence of rhombohedral (R) and tetragonal (T) phases inside nanodomains, that is, a structural origin for the R–T phase boundary in the present KNN system. Hence, the physical origin of high piezoelectric performance can be attributed to a nearly vanishing polarization anisotropy and thus low domain wall energy, facilitating easy polarization rotation between different states under an external field.