Little-Parks effect of fine superconducting Pb networks fabricated by focused-ion-beam microscope

Abstract The Little-Parks effect is originally known as a phenomenon, where a critical temperature T c of the superconducting cylinder oscillates as a function of the applied magnetic field with a period of Φ 0 [R.D. Parks, W.A. Little, Phys. Rev. 133 (1964) A97]. It has been well known that a sort of the Little-Parks effect occurs in superconducting network samples, too [B. Pannetier, J. Chaussy, R. Rammal, J.C. Villegier, Phys. Rev. Lett. 53 (1984) 1845]. In this work we intend to prepare fine superconducting networks with the aid of a focused-ion-beam (FIB) microscope. It is very convenient to prepare various kinds of superconducting networks without preparing photo-masks in lithography. The networks thus obtained are examined by using a confocal laser microscope as well as an atomic force microscope. We developed the measurement system to trace a critical temperature T c as a function of the applied field. The LabVIEW-based system is designed to measure the Little-Parks effect automatically for various sorts of superconducting networks.