Synthesis, crystal structure and properties of a quaternary oxide with a new structure type, BiGaTi4O11
Synthesis, crystal structure and properties of a quaternary oxide with a new structure type, BiGaTi4O11
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新型结构类型四元氧化物BiGaTi4O11的合成、晶体结构及性能
DOI：
10.1107/s2053229619005989
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Yuji Masubuchi
中科院分区：
文献类型：
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作者：
Hisanori Yamane;Ryota Yagi;Akira Hosono;Yuji Masubuchi
通过在空气中加热二元氧化物的混合物，在1373 K下制备了一种新的四元氧化物BiGaTi_4 O_（11）（铋镓四钛十一氧化物）。 BiGaTi 4 O 11熔体在1487 K和棱柱形单晶体从一个样品在1523 K熔化，并通过炉冷却固化。 利用单晶X射线衍射分析了BiGaTi 4 O 11的结构，其为在空间群Cmcm中结晶的新型结构。一个Bi 3+位点由9个O2−阴离子配位，三个氧配位的八面体位点统计上被Ga 3+和Ti 4+阳离子占据。对于多晶陶瓷样品，在150 Hz-1 MHz下测量到在297-448 K的温度范围内相对介电常数为46，温度系数为57 ppm K−1，介电损耗tan δ小于0.01。 在1073 K下，交流阻抗谱法和直流法测得的电导率分别为1.16 × 10−4和1.14 × 10−4 S cm−1，这表明电子和/或空穴在高温下是导电载流子。 由漫反射分析的结果估计的光学带隙为2.9- 3.0eV，而由导电活化能获得的带隙为3.5eV。
A new quaternary oxide, BiGaTi4O11 (bismuth gallium tetratitanium undecaoxide), was prepared by heating a mixture of the binary oxides at 1373 K in air. BiGaTi4O11 melts at 1487 K and prismatic single crystals were obtained from a sample melted at 1523 K and solidified by furnace cooling. The structure of BiGaTi4O11 was analyzed using single-crystal X-ray diffraction to be of a new type that crystallized in the space group Cmcm. A Bi3+ site is coordinated by nine O2− anions, and three oxygen-coordinated octahedral sites are statistically occupied by Ga3+ and Ti4+ cations. A relative dielectric constant of 46 with a temperature coefficient of 57 ppm K−1 in the temperature range 297–448 K was measured for a polycrystalline ceramic sample at 150 Hz–1 MHz with a dielectric loss tan δ of less than 0.01. Electrical resistivities measured at 1073 K by alternating-current impedance spectroscopic and direct-current methods were 1.16 × 10−4 and 1.14 × 10−4 S cm−1, respectively, which indicates that electrons and/or holes were conduction carriers at high temperature. The optical band gap estimated by the results of diffuse reflectance analysis was 2.9–3.0 eV, while the band gap obtained from the activation energy for electrical conduction was 3.5 eV.