Nature of Phase Transitions of Superconducting Wire Networks in a Magnetic Field

X. S. Ling; H. J. Lezec; M. J. Higgins; J. S. Tsai; J. Fujita; H. Numata; Y. Nakamura; Y. Ochiai; Chao Tang; P. M. Chaikin; S. Bhattacharya

doi:10.1103/PhysRevLett.76.2989

Nature of Phase Transitions of Superconducting Wire Networks in a Magnetic Field

X. S. Ling, H. J. Lezec, M. J. Higgins, J. S. Tsai, J. Fujita, H. Numata, Y. Nakamura, Y. Ochiai, Chao Tang, P. M. Chaikin, and S. Bhattacharya

Phys. Rev. Lett. 76, 2989 – Published 15 April 1996; Erratum Phys. Rev. Lett. 77, 410 (1996)

Abstract

We study $I - V$ characteristics of periodic square Nb wire networks as a function of temperature in a transverse magnetic field, with a focus on three fillings 2/5, 1/2, and 0.618 that represent very different levels of incommensurability. For all three fillings, a scaling behavior of $I - V$ characteristics is found, suggesting a finite temperature continuous superconducting phase transition. The low-temperature $I - V$ characteristics are found to have an exponential form, indicative of the domain-wall excitations.