VORTEX LATTICE AUTOCORRELATION FUNCTION STUDIED BY AN ATOMIC-BEAM TECHNIQUE

We have developed an atomic beam technique for studying the Abrikosov vortex lattice. Atoms skimming the surface of a superconductor in the intermediate state experience a temporally fluctuating magnetic field due to the spatial variation of the local magnetic induction. This fie ld may drive transitions in the atoms. By measuring the transition pro bability as a function of atom velocity, we study the vortex lattice a utocorrelation function along the direction of travel. We also determi ne the penetration depth. We demonstrate the technique by studying the Vortex lattice of a niobium film.