The Pinning Force and Critical Current in NbTi Superconducting Wire with Plate-Like α-Ti Precipitates
Analytical expressions for the pinning force density Fp and the critical current density Jc of NbTi wire having plate-like α-Ti precipitates are derived from Matsushita’s statistical theory and the local free-energy density function. These expressions show that both Fp and Jc are an increasing function of the volume fraction of α-Ti plates, and proportional to the square root of the average thickness of the plates. When the average separation of α-Ti plates is about equal to the spacing of the fluxoids Fp and Jc have their maxima. The calculated results from our expressions are compared with measurements. The calculated and measured results are in rather good agreement.
KeywordsCritical Current Density Flux Line Average Separation Wire Axis Local Order Parameter
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