Fabrication and properties of ac-dc superconducting rectifier

Abstract

Magnetron sputtering, electron beam lithography and etching techniques allow us to fabricate Nb thin films on array of periodic nonsuperconducting nanometric triangles. These asymmetric pinning potentials induce a ratchet effect on the vortex lattice motion: injecting an ac current on the sample yields a dc voltage. This rectification effect does not depend on the ac frequency in the kHz range. The effect occurs for magnetic as well as nonmagnetic pinning centers. The rectification is enhanced at lower temperatures.