Intermediate vortex-flux properties of polycrystalline Y1Ba2Cu3O7-δ superconductors

Rotational magnetization-vector measurements have been performed on polycrystalline Y1Ba2Cu3O7-delta superconductors under various magnetic fields at 4.2 K. The experimental results show that the vortex-flux density has three parts: a weak pinning part which stays at a fixed angle relative to the magnetic field, a strong pinning part which rotates rigidly with the sample and which has the same magnitude as the sample rotation, and an intermediate pinning part which rotates rigidly with the sample, but whose magnitude changes with the sample rotation. These results have been explained by using the strength distribution of the vortex pinning torque and the repulsive intervortex torque.