Irradiation Effect of Slow Neutrons on Mechanical Behaviour Related to Flux Pinning In YBa₂Cu₃O_y

Abstract

Internal friction and modulus in YBa2Cu3Oy, which are related to flux pinning, were examined by means of the vibrating reed technique before and after the slow neutron irradiation to different fluences. Both the decrease of mechanical dissipation and the increase of the modulus associated with strongly enhanced flux pinning were observed in a sample irradiated up to a suitable fluence. However, a decrease of modulus and magnetic hysteresis loop was found after further irradiation. A change in the microstructure of the irradiated material is used to explain the observed phenomena.