ENHANCEMENT OF CYSTAL GROWTH IN MELT TEXTURING Ca-DOPED Y-Ba-Cu-O SUPERCONDUCTORS

摘要

Doping of Ca in YBa_2Cu_3O_(7-x) (Y123) has been reported to enhance the critical current density in Y123. However, fabrication of large Ca doped Y123 single crystals remains challenging. The cooling temperature and the growth rate of Ca doped Y123 samples as a function of Ca concentrations is studied. Isothermal cooling at varied temperatures (1003, 1005, 1006 and 1009℃) is applied to Ca doped Y123 samples in order to determine the optimal growth condition of the samples. It is found that the optimal growth rates occur at the undercooling ranges from 10 to 30℃ in samples with Ca concentration ranges from 7.5 to 25 mol%, respectively.