Pinning performance of (Nd_0.33Eu_0.2Gd _0.47)Ba₂Cu₃O_y single crystal

We present data on the flux pinning performance of a twinned (Nd _0.33Eu_0.2Gd_0.47)Ba₂Cu ₃O_y single crystal with a strip-like surface structure, in the temperature range 65 K to 90 K. The critical current density J_c, the pinning force density F(=BJ_c), and the logarithmic dynamic relaxation rate Q were determined from the magnetic hysteresis loops (MHLs) measured by vibrating sample magnetometer up to 9 Tesla. At 65 K, the MHL featured a strong second peak with the top slightly depressed by twin plane channeling. This effect continuously decreased with increasing temperature but persisted up to 84 K. The second peak decreased faster with increasing temperature than the central one. None of the J_c(B) and F(B) dependences scaled, let alone in a narrow range of T. This fact, together with the multiple linear character of the Q(B) curve, indicated a strong effect of twin channeling on the crystal's pinning performance. No special effect due to the strip-like structure was recognized.