Anisotropic vortex cross-flux effects in grain-oriented YBa2Cu3O7

After cooling to 4.2 K in a field Hcool parallel (or normal) to the c axis and then removing Hcool, the sample was subjected to an increasing field H normal (or parallel) to c and the longitudinal and transverse magnetizations relative to H were measured simultaneously. The vortex flux produced by Hcool along c persists and inhibits the creation by H of vortex flux in the a-b plane. However, the creation of the latter does not require a threshold value of H. The vortex flux produced by Hcool in the a-b plane diminishes rapidly with increasing H along c, and there are essentially no cross-flux effects. Thus, these effects are largely governed by the strength of the initial flux pinning, which is highly anisotropic