メゾスコピック走査ホールプローブ顕微鏡の開発-極微小領域における不均質磁束密度分布の定量解析に向けて-

1.量子化磁通量的观测：主要采用Y123涂层导体和多晶块材，成功地观测到了局域磁场分布和晶界及附近磁场的扰动。在Ag/Bi 2223带材中观察到几微米和几十微米的磁场不均匀性。这些结果与小角中子散射强度和磁场下的超导性质进行了比较。电流磁场分布转换程序的开发：开发了两种类型的程序。(1)从观测磁场中得到电流分布的方法。对于薄膜样品，利用毕奥-萨伐尔定律可以得到电流分布。(2)将计算的磁场分布与观测数据进行比较的方法，其中假设模型电流分布。这两个程序现在都用于分析实验数据3。量子化磁通的动力学：根据高分辨率SHPS和SQUID 4的数据，研究了磁通的动力学行为和蠕变现象。临界电流密度的不均匀性：使用高分辨率SHPS测量了Ag/Bi 2223带材中的磁通分布。分布的不均匀性与由于微观结构的不均匀性而引起的局部输运电流分布密切相关

1. Observation, of quantised magnetic flux : Using mainly Y123 coated conductor and polycrystalline bulk, we could successfully observed the local magnetic field distribution and the disturbance of magnetic field at and near grain boundary. The magnetic field inhomogeneity with several and several ten micrometers was observed in the Ag/Bi2223 tapes. These results were compared with the small angle neutron scattering intensity and the superconducting property under magnetic field2. Development of conversion program about the current magnetic field distribution : Two type of programs have been developed. (1) Method to get current distribution from the observed magnetic field. For thin film sample, it is possible to get current distribution by using Biot-Savart law. (2) Method to compare the calculated magnetic field distribution with the observed data, where a model current distribution is assumed. Both programs are now used for analyzing the experimental data3. Dynamics of quantized magnetic flux : Dynamical behavior and creep phenomenon of magnetic flux have been investigated based on the data by means of high resolution SHPS and SQUID4. Inhomogeneity of critical current density : Magnetic flux distribution in Ag/Bi2223 tape was measured using high resolution SHPS. The inhomogeneity of the distribution has been discussed to correlate strongly with the local transport current distribution attributing to the inhomogeneity of microstructure