高温超导多晶材料临界电流密度应变效应的理论研究

The strain sensitivity of the critical current density of high-temperature superconducting materials is an important problem within the field of superconducting applications in recent years. Since this problem is related to the elastic - electric - magnetic multi-physicals coupling, as well as the complexity of the material microstructure, the treatments of this problem have been limited to experimental studies and empirical formulas based on the experimental datas. The theoretical studies on the mechanism of this problem have been rarely seen in public reports. The applicant has initially established the framework of the elastic-electric coupling study in type II superconductors based on the modified GL theory.Based on our previous work, we intends to research the critical current density weakening mechanism of the superconducting polycrystalline thin films under mechanical deformations in this project. We focus on the analysis that the impact of the grain boundary on the superconducting electronic transport properties of polycrystalline superconductors, considering the relation between the weak link properties in the grain boundaries of the superconductors and the mechanical deformations. The modified GL theory can be used to research the coupling mechanism between the superconducting properties and the stress(strain).Besides,the interaction between the stress fields and the dislocations and further the changes in the carrier density has also been taken into account. In addition, in this project we can analyze the superconductivities of various types of high-temperature superconductors under different modes of deformation.The results of this study will be helpful for people to deepen their understanding of high-temperature superconductors,it also has some significance for engineering applications of high temperature superconductors.

高温超导材料临界电流密度的应变敏感性是近年来超导应用领域备受关注的一个重要问题。由于这一问题涉及到力-电-磁多物理场的耦合以及材料微观结构的复杂性，目前这一问题的处理方法还多局限于实验研究以及基于实验数据拟合的经验公式等，而对于其机理方面的研究还极少见诸报导。借助于申请人在II型超导体力-电耦合特性方面已初步建立的基于修正GL理论的基本框架和研究思路，本课题拟进一步针对高温超导多晶薄膜在力学变形下临界电流密度的弱化机制展开研究。着重分析晶界对于多晶超导体内超导电子输运特性的影响，基于修正的GL理论研究晶界内超导电性与应力应变之间的耦合规律；并考虑应力场同位错之间的相互作用及对载流子密度的改变；数值模拟不同变形模式对于各类超导体超导电性的影响。通过本课题的研究，既有助于人们加深对高温超导体载流特性的微观认识，同时也对高温超导体的工程应用具有一定的指导意义。

高温超导材料临界电流密度的应变效应是近年来超导应用领域备受关注的一个重要课题。这一课题涉及到力-电-磁多物理场的耦合以及材料复杂微结构，目前针对这一问题的研究方法还大多局限于实验研究以及基于实验数据拟合的经验公式等，而对于其机理方面的研究还极少见诸报导。借助于申请人在II型超导体力-电耦合特性方面已初步建立的基于修正GL理论的基本框架和研究思路，本课题针对高温超导多晶薄膜在力学变形下临界电流密度的弱化机制展开研究。本研究着重分析了晶界对于多晶超导体内超导电子输运特性的影响，基于修正的GL理论研究晶界内超导电性与应力应变之间的耦合规律；并考虑应力场同位错之间的相互作用及对载流子密度的改变；分析了夹杂对于超导体临界电流密度以及裂纹尖端应力强度因子影响；研究了晶界对于超导体应力和变形的影响。本课题的研究方法和成果既有助于人们加深对高温超导多晶材料载流特性的微观认识，同时也对高温超导体的工程应用具有一定的指导意义。