Irradiation effects in Ba 2YCu 3O 7 superconductor

Abstract

Superconducting property changes induced by electron, neutron and ion irradiations in Ba 2YCu 3O 7 pellets and thin films were reviewed in consideration of the critical current density enhancement with radiation-produced defects. The transition temperature decreases almost proportionally to the fluence concurrently with a linear increase in normal state resistivity at an early stage of the irradiations. The ratio of the degradation rate for the transition temperature to that for the resistivity is in the range from 0.4 to 0.8 K/μΩ·m in the pellets irradiated with MeV-electrons and reactor-neutrons and 0.1 to 2 K/μΩ·m for high quality thin film irradiated with 600 keV Ar-ions. The critical magnetization current density in sintered pellets is increased by irradiation with electrons, neutrons and high-energy Xe ions to relatively low fluences where the transition temperature is decreased by about 1 K or less. The enhancement is significant in higher magnetic fields for the electron and neutron irradiated samples. Furthermore, the critical transport current density is increased in magnetic fields more than 1 T in an oriented thin film irradiated with 25 MeV 16O ions to a fluence that decreases the transition temperature by about 3 K.