date:RIKEN, Inst Phys & Chem Res, Digital Mat Lab, Frontier Res Syst, Wako, Saitama 3510198, Japan; Univ Camerino, Ist Nazl Fis Mat, I-62032 Camerino, Italy; Katholieke Univ Leuven, Vaste Stof Fys & Magnetisme Lab, B-3001 Heverlee, Belgium; Univ Michigan, Dept Phys, Ctr Theoret Phys, Ann Arbor, MI 48109 USA
We study the transport of vortices in superconductors with square arrays of asymmetric pinning wells when applying an alternating electrical current. This system can induce a net rectifying or diode effect for the vortex motion, including collective stepmotor-type dynamics, where many vortices move forward a controlled and exact number of pin-lattice-spacings at each cycle of the AC driving force. This system exhibits a remarkable net DC response with striking sawtooth-type oscillations, which we have studied as a function of several parameters (e.g., field H, Amplitude of drive). We analytically derive the main numerical features obtained here. (C) 2004 Elsevier B.V. All rights reserved.