Contents

08 March 1996
Vol 271, Issue 5254

About The Cover

Interaction of magnetic vortices (green spots) with pinning centers (red holes, 3.3 micrometers apart) in a superconductor observed in real time by Lorentz microscopy with a field emission electron microscope. The vortex lattice is disturbed at the pinning centers to form domain structures. "Vortex rivers" flow intermittently like avalanches along the domain boundary. See 1393 and the Perspective on 1373. [Image: T. Matsuda, K. Harada, H. Kasai, O. Kamimura, A. Tonomura]