利用简单的液相合成方法,在室温条件下制备了KCoF3粉末状产物。通过X射线粉末衍射(XRD)和扫描电镜(SEM)对其物相结构和形貌进行了表征,结果表明:KCoF3是一种ABC3型的钙钛矿结构,属于立方晶系,空间群为pm-3m[221]。利用Rietveld粉末衍射峰形拟合方法对化合物KCoF3的X-射线粉末衍射数据进行分析,并对其结构进行精修,表明其晶格常数为口=4.076(2)A,晶胞体积为67.727(7)硝,每个单胞含1个化学式(Z=1),计算密度为Dc=3.812(1)g/cm3。而对KCoF3电学性能的研究表明,在273K附近存在Co原子自旋态的改变,高自旋态向低自旋态的变化影响了Co原子间的超交换作用,进而影响了电输运行为。
The authors use simple aqueous synthesis method to prepare pure complex fluoride of KCoF3 crystal powder successfully at room temperature. The sample is characterized by X-ray diffraction (XRD), scan electron microscopy (SEM) and the result proves that the product is KCoF3, of perovskite- structure and a cube. The space group is pm-3m [221], with a=4. 076(2) A, the cell volume is 67. 727(7) X3 each cell includes one KCoF3, and the calculate density is 3. 812(1) g/cm3. As to the electrical proper- ty of KCoF3, there is a spin state transition near 273 K because the Co3+ changes spin state from high spin state to low spin state, which varies the superexchange effect between Co3+ atoms.