Magnetization measurements have been performed on c-axis oriented films of Bi2Sr2CaCu2O8 and YBa2Cu3O7-δ in wide ranges of the temperature T and magnetic field H. For fields along the c-axis, we found a universal relation between the reduced quantity of magnetization hysteresis m=ΔM/ΔM0 and the reduced field h=H/H*, where ΔM0 is the hysteresis of magnetization ΔM at H=0 and H* is the irreversibility field. The relation is practically independent of temperature and materials investigated. The hysteresis m decreases exponentially with increasing h except h∼1, while the field dependence deviates from the exponential decay for h∼1 and m=0 at h=1. This dependence of m can be interpreted within the framework of the flux creep model in wh ich the logarithmic current dependence at high current density and the linear current dependence at low density are assumed for the effective pinning potential.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering