Magnetic Relaxation in YBaCuO Systems Prepared by Modified Melt-Textured Growth Method

Magnetic relaxation in YBa2Cu3O7 high-Tc superconductor system samples prepared by a modified melt-textured growth method was investigated. The relaxation rate S, given by M^¿1 dM/d log(t), is independent of the magnetic field and temperature below a given temperature T0, which decreases with increasing magnetic field. The pinning potential, evaluated from temperature-independent S values, increases with temperature, but the behavior is not intrinsic. However, at temperatures above T0, S increases with temperature, giving a potential dependent on log(Jc).