Experimental investigation of a local mixed state induced by a small ferroparticle in YBaCuO films

A scanning Hall probe was used to carry out direct local measurements of the characteristics of a mixed state induced by a magnetic field of a small ferromagnetic particle in thin film YBaCuO samples. The results showed evidence for an extremely low energy barrier for entry of vortex half-loops into high quality films. It was also observed that the half-loops further broke down into vortex-antivortex pairs which was consistent with the Josephson medium model.