Bi-Sr-Ca-Cu-O系超伝導体の熱処理による物性変化

概要

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This experiment was carried out to investigate the effect of heat treatment on the physical properties such as resisitivity, Hall coefficient and magnetization of Bi_2Sr_2CaCu_2O_<8+δ> ceramics and single crystals. Bi_2Sr_2CaCu_2O_<8+δ> single-crystals were grown using by the Traveling Solvent Floating Zone (TSFZ) method. The result of Hall effect shows that the carriers have the hole characteristic in this system. The hole number increases and Tc decrease with increasing oxidation. The Hall mobility is independent of the heat treatments for Bi_2Sr_2CaCu_2O_<8+δ> ceramics. This result indicates that oxygens enter and leave sites on a plain other than the CuO_2 plain by the heat treatment in Bi_2Sr_2CaCu_2O_<8+δ> ceramics. The pinning density of the magnetic flux is increased by quenching in the ceramics but it shows little change in the single crystal. In Bi_2Sr_2CaCu_2O_<8+δ> s single crystal, however, we find that the pinning density of the flux increases with the decrease in the sample thickness.
明治大学の論文