Angular scaling of the irreversible magnetization in Y-Ba-Cu-O single crystals.

The angular dependence of the irreversible magnetization of Y−Ba−Cu−O crystals is measured by means of torque and SQUID magnetometry. Close toT c , the magnetization depends only on the c axis component µ0 H cos θ of the applied magnetic field. The fishtail effect observed in this temperature regime for µ0 H ≤ 1.5 T is essentially related to the magnetic moment parallel to the c axis. At intermediate temperatures, the irreversible torque at a given magnetic field scales as\(\tau _{irr} \propto sin 2\theta /\sqrt {sin^2 \theta + \alpha ^2 \cos ^2 \theta } \), where α isnot directly related to the intrinsic anisotropy of Y−Ba−Cu−O.