STRUCTURE AND MAGNETIZATION OF A 2-DIMENSIONAL VORTEX LIQUID IN THE PRESENCE OF STRONG PINNING

The structure of a two-dimensional vortex liquid in the presence of st rong pinning centers is investigated using the density-functional form alism. Short-range positional and angular correlations in the liquid r esult in an effective interaction between pinned vortices, mediated by the unpinned ones. This effective interaction is short range and it o scillates with the intervortex distance. Matching of this oscillation with a periodic array of strong pinning centers leads to anomalies in the reversible magnetization M(H) at the ''matching field'' B-phi and some of its harmonics.