Study of the Upper Critical Field Hc2 for High-Tc Superconductors in Pulsed High Magnetic Fields

Abstract

The magnetoresistance and the magnetization in high-Tc superconductors Y–Ba–Cu–O and Ln–Ba–Cu–O (Ln=Er and Ho) were measured in pulsed high magnetic fields up to 40T. The values of dHc2/dT are estimated to be -1.8, -1.8 and -1.2T/K for Y, Er and Ho compounds, respectively. The magnetization of the Er and Ho compounds show a paramagnetic behavior at high magnetic fields even below Tc, but a considerable deviation from the free ion magnetizations was observed.