Magnetization jumps in YBa 2Cu 3O 7 single crystal, up to 18T

Abstract

The magnetization of a large single crystal (27 mg) of YBa 2Cu 3O 7 exhibits several new features associated to the anisotropy (and sample size) : for H // c axis large magnetization jumps are observed below about 15 K. The magnetization jumps are smaller, less spaced and observed only below 7 K for H ⊥ c. At high temperature the hysteresis loops, M(H), are convex lens shaped which gives a larger density of currents in high fields. The critical currents (6.8 10 5 A/cm 2 or 2.8 10 5A/cm 2 for H parallel or perpendicular to the c axis, at 4.2 K) can be compared with values obtained for much smaller crystals.