Effect of SHI IRRADIATION on CRITICAL CURRENT DENSITY in Y1-xCaxBa2Cu3O7-δ Thick Film with Y2O3 Addition

Abstract

Y1-xCaxBa2Cu3O7-d (x = 0.1) + Y2O3 (10 wt.%) composite thick film has been prepared by diffusion reaction technique. The samples are irradiated with 200 Mev Ag ions. X-ray diffraction, SEM reveals the micro structural changes on the irradiated samples. Using Beans critical state model critical current density was estimated from the width of magnetization loops. The enhancement of Jc from1.4x104Acm-2 to 6.7x104 Acm-2 with irradiation upto fluence 5x1011ion-cm-2 in YCaBCO samples is observed indicating that flux pinning increases due to the creation of columnar defects induced by irradiation. Addition of Y2O3 increases the Jc in the pristine sample to 8.3x104Acm-2 but decreases with increasing fluence. Like the columnar tracks, the insulating inclusions Y2O3 causes Jc increase by the same process of flux pinning. Either increasing the volume fraction of the inclusions or irradiating the composites might degrade the superconducting volume fraction and cause Jc decrease. Degradation of the superconducting volume fraction has been observed as Tc is lowered in the composite. As the defects (linear defects with columnar defects due to irradiation) are more, the interaction energy between vortex and defects dominate over the pinning energy. Hence the pinning sites are not used effectively. Thus Jc starts to decrease with irradiation.