Irradiation effect on the pinning potential of YBCO single crystal

摘要

The results of the magnetization measurements of single crystal of YBa_2Cu_3O_y with Tc = 91 K are adduced. The temperature, field and time dependencies of the remnant magnetization M_r(T, B, t) were obtained using VSM method for the temperature range from 4.2 K to 75 K for H‖c configuration. The single crystal has been irradiated by the fast electrons (E = 4 MeV) with fluences up to 2·10~(18) cm~(-2). The relaxation of M_r(t) obeys to the logarithmic law for the time interval t = 1 h for whole temperature range except the ～30 - 50 K interval for starting and irradiated states. After irradiation the J_c decrease despite the flux creep reduction. The irradiation become less effective at high temperatures. The results are discussed in frame of conventional flux creep theory and of the interaction model of radiation defects with the background ones.