Melting transition of vortex matter in YBa2Cu3Oy with various oxygen contents

摘要

The effect of oxygen content on the vortex phase diagram of untwinned YBa2Cu3Oy (YBCO) single crystals has been studied by magnetization and resistivity measurements in high magnetic fields up to 30 T. The cantilever magnetometry with a capacitance torque meter has been developed for precise magnetization measurement in high magnetic field. As for fully oxidized and optimally doped YBCO, the magnetic properties near the first-order vortex lattice melting transition line are discussed in comparison with the vortex phase diagram obtained from the resistivity measurement. (C) 2001 Elsevier Science B.V. All rights reserved. [References: 24]