Ferroelectric BaTaO2N Crystals Grown in a BaCN2 Flux
Ferroelectric BaTaO2N Crystals Grown in a BaCN2 Flux
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在 BaCN2 助熔剂中生长的铁电 BaTaO2N 晶体
DOI：
10.1021/acs.inorgchem.9b02917
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发表时间：
2019
影响因子：
4.6
通讯作者：
Mitsuru ITOH and Shinichi KIKKAWA
中科院分区：
文献类型：
--
作者：
Akira HOSONO;Yuji MASUBUCHI;Shintaro YASUI;Masaki TAKESADA;Takashi ENDO;Mikio HIGUCHI;Mitsuru ITOH and Shinichi KIKKAWA
钙钛矿型氮氧化物BaTaO_2N具有很大的介电常数，且其介电常数几乎与温度无关，因此受到人们的广泛关注。其介电特性归因于平均立方晶体结构中的极性纳米区（PNR）。在本研究中，在BaTaO_2 N晶体上观察到偏振饱和产生蝴蝶状的压电响应力显微镜（PFM）信号。用BaCN_2助熔剂生长了尺寸达3.1 μm的BaTaO_2N微红色微晶。晶粒生长进行通过形成Ruddlesden-Popper型氮氧化物从BaTaO 2N粉末和熔融BaCN 2之间的反应。它们的电性能进行了研究，特别小心，因为小尺寸的晶体使用PFM。他们被发现比它的陶瓷绝缘性高得多。首次在氧氮化物钙钛矿晶体上观察到了完全相反转的铁电性。在测量中观察到50-60 V的大电导率。这种铁电性归因于PNR诱导的极性键之间的cis型TaO 4 N2八面体。
Perovskite-type oxynitride BaTaO2N has been attracting attention for its large dielectric constant, which is almost independent of the temperature by measurements on its ceramics. Its dielectric characteristics are attributed to polar nanoregions (PNRs) in the average cubic crystal structure. Polarization saturation to produce a butterfly-like piezoresponse force microscopy (PFM) signal was observed on BaTaO2N crystals in the present study. Reddish crystallites of BaTaO2N of up to 3.1 μm in size were grown using a BaCN2flux. Grain growth proceeded through the formation of a Ruddlesden–Popper-type oxynitride from the reaction between BaTaO2N powder and molten BaCN2. Their electrical property was studied using PFM with special care because of the small size of the crystals. They were found to be much more highly insulating than its ceramics. Ferroelectricity with complete phase inversion was observed on an oxynitride perovskite crystal for the first time. A large coercivity of 50–60 V was observed in the measurement. Such ferroelectricity is ascribed to the PNRs induced by the polar linkages betweencis-type TaO4N2octahedra.