Effect of short-time magnetic relaxation on hysteresis curves in single-crystal Bi2Sr2CaCu2Ox

We have studied the role of short relaxation time on magnetic hysteresis in a Bi2Sr2CaCu2Ox single crystal. Effects were examined by comparing isother mal magnetization curves obtained over a range of temperatures as a functio n of the applied magnetic field, H, for magnetic field ramp rates of 3 and 30 Oe/s. At low temperature, a second magnetization peak, H-p, was produced by differences in magnetic relaxation occurring over a short period during the initial stage of relaxation. The data suggested an absence of pinning crossover for H approximate to H-p.