Ti5Nb人工钉扎中心NbTi超导体的磁通钉扎机制分析

Flux Pinning Mechanism in Superconducting NbTi Composites with Ti5Nb Artificial Pinning Center

采用棒基组合的装配方法,用热挤压和冷加工相结合的工艺制备了岛状Ti5Nb人工钉扎中心NbTi超导体,其中Ti5Nb体积含量为10%。通过对此超导体进行详细的磁通钉扎机制分析,认为样品的磁通钉扎力特征主要由正常相钉扎和Dk钉扎相结合的机制决定。根据分析的结果,采用多源标度方法,很好地拟合了不同线径样品的磁通钉扎力密度随磁场变化的曲线。拟合的结果表明:样品在较低场下的性能主要由正常相钉扎机制决定,而在较高场下的性能主要由Dk钉扎机制决定。并且随着线径的减小,正常相钉扎力密度和Dk钉扎力密度均有不同程度的提高。

Flux pinning mechanism in superconducting NbTi composites with Ti5wt%Nb artificial pinning center is analyzed in detail. The results show that F-p(B) mainly depends on normal metal pinning mechanism and Deltakappa pinning mechanism. The results suggeste that both normal metal pinning mechanism and Deltakappa pinning mechanism are very important. The value of F-p(B) in lower magnetic field is mainly dominated by normal metal pinning mechanism and the value of F-p(B) in higher magnetic field is mainly dominated by Deltakappa pinning mechanism. The function value of Fp(B) dependant on normal metal pinning mechanism and Deltakappa pinning mechanism increase respectively with the decrease of the wire diameter.