Quantitative description of a very high critical current density Nb-Ti superconductor during its final optimization strain. II: Flux pinning mechanisms
Quantitative description of a very high critical current density Nb-Ti superconductor during its final optimization strain. II: Flux pinning mechanisms
复制标题
对最终优化应变期间极高临界电流密度 Nb-Ti 超导体的定量描述。
DOI：
10.1063/1.343625
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发表时间：
1989
影响因子：
3.2
通讯作者：
D. Larbalestier
中科院分区：
文献类型：
--
作者：
C. Meingast;D. Larbalestier
在精心制作的Nb - 48wt . % Ti复合材料中，研究了α - Ti沉淀的通量钉住，该复合材料具有很高的临界电流密度和宏观上相当均匀的沉淀阵列。研究了在大拉伸应变作用下析出相厚度（tppt）与相干长度（ξ）的比值随电场（0-15 T）和温度（2.3 K-Tc）的变化规律。令人惊讶的是，最大体积钉住力（Fp）发生在tppt/2ξ≂0.1，沉淀间距约为通量间距的八分之一，这表明通量钉住发生在沉淀簇上。与早期的研究相反，没有观察到Fp的严格温度结垢；随着温度的升高，钉住力峰值向较低的还原场移动。在微观结构最细的情况下，影响最大。这种非标度被解释为具有不同场和温度依赖关系的两种钉钉机制。在低还原场和温度下…
Flux pinning by α‐Ti precipitates has been studied in a carefully made Nb 48 wt. % Ti composite having very high critical current density and a macroscopically rather uniform precipitate array. The pinning was studied as a function of field (0–15 T) and temperature (2.3 K—Tc) for a ratio of the precipitate thickness (tppt) and the coherence length (ξ) which was varied between 10 and 0.1 by a large drawing strain. Surprisingly, the maximum bulk pinning force (Fp) occurred for tppt/2ξ≂0.1 and a precipitate spacing about one‐eighth the fluxon spacing, suggesting that the flux pinning occurs at clusters of precipitates. In contrast to earlier studies, strict temperature scaling of Fp was not observed; the peak of the pinning force shifted to lower reduced fields as the temperature increased. The effect was largest for the finest scale microstructure. This nonscaling is interpreted in terms of two pinning mechanisms having different field and temperature dependencies. At low reduced fields, and at temperatures...