Pinning of magnetic flux lines in Y-Ba-Cu-O superconductors by neutron irradiation and chemical route

The increase of critical magnetization current due to pinning of magnetic flux lines in Y-Ba-Cu-O superconductors has been investigated. The methods utilized were either irradiation by fast neutrons or addition of yttria inclusions prior to processing. The Y-Ba-Cu-O superconductors were prepared as plates (20 to 40 cm in length) using melt texturing method. Samples were irradiated using doses of 2/spl times/10/sup 21/ to 5/spl times/10/sup 22/ neutrons pr. sq. m. According to magnetization measurements, the critical current density is improved /spl sim/3 and /spl sim/12 times at magnetic fields of 0.07 and 1 tesla respectively. Thus, at 1 tesla the critical current density was improved from 290 to 3500 A/cm/sup 2/ by an irradiation of 1/spl times/10/sup 22/ neutrons/spl middot/m/sup -2/. Addition of yttria results in formation of 1 to 20 /spl mu/m large inclusion of Y/sub 2/BaCuO/sub 5/ in the superconducting material. The critical current characteristics show a peak-effect at 1 to 2 tesla, with critical currents comparable to irradiated samples. Melt textured single crystals have equal high critical current densities at these applied magnetic fields.