Determination of Cu3+Cu2+ ratio in the superconductor YBa2Cu3O8−x
Determination of Cu3+Cu2+ ratio in the superconductor YBa2Cu3O8−x
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DOI：
10.1016/0022-4596(87)90025-9
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发表时间：
1987-07
影响因子：
3.3
通讯作者：
D. C. Harris;T. A. Hewston
中科院分区：
文献类型：
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作者：
D. C. Harris;T. A. Hewston
对不同实验室制备的YBa/sub 2/Cu/sub 3/O/sub 8-x/3种高温超导体样品，在不同的最终加热条件下，测定了样品的总铜含量和Cu/sup 3 +//Cu/sup 2 +/比。样品的X射线衍射图给出了类似的正交晶胞参数。用碘量滴定法和氢气氛下热重分析法测定了YBa/sub 2/Cu/sup 3 +//sub 3-2x/Cu/sup 2 +//sub 2x/O/sub 8-x/中的x值。最终加热温度、冷却方法和滴定测量的x值为：900/sup 0/C，0/sub 2/-退火/缓慢冷却，x = 1.06（5）; 950/sup 0/C，空气淬火，x = 1.35（5）; 930/sup 0/C，空气/缓慢冷却，x = 1.13（4）。近似T/sub c/值，从磁化率曲线的起始温度，分别为93，98和100 K。
The total copper content and Cu/sup 3 +//Cu/sup 2 +/ ratio were determined for three samples of the high-temperature (T/sub c/ = 90 to 100 K) super conductor, YBa/sub 2/Cu/sub 3/O/sub 8-x/, prepared in different laboratories under various final heating conditions. The x-ray diffraction patterns for the samples gave similar orthorhombic unit cell parameters. Iodometric titration and thermogravimetric analysis under hydrogen were used to determine the x-value in the formula YBa/sub 2/Cu/sup 3 +//sub 3-2x/Cu/sup 2 +//sub 2x/O/sub 8-x/. The final heating temperatures, cooling methods, and x-values from the titration measurements are: 900/sup 0/C, O/sub 2/-annealed/slow-cooled, x = 1.06(5); 950/sup 0/C, air-quenched, x = 1.35(5); 930/sup 0/C, air/slow-cooled, x = 1.13(4). The approximate T/sub c/ values, taken as onset temperatures from magnetic susceptibility curves, are 93, 98, and 100 K, respectively.