Flux pinning by magnetic dots with in-plane magnetization

Flux pinning is studied in superconducting Pb films with a lattice of sub-micron Co dots. Matching anomalies are observed in the magnetization curves, corresponding to stable vortex configurations in the periodic pinning potential created by the lattice. By comparing magnetic dots (Co) with different stray field strengths and non-magnetic dots (Ge, Au), a pronounced enhancement of the pinning efficiency by the local stray field of the Co dots is demonstrated. (C) 2000 Elsevier Science B.V. All rights reserved.