Superconducting Cu₂Mo₆S₈ thin films deposited in-situ by laser ablation on R-plane sapphire^*

Laboratoire de Chimie du Solide et Inorganique Moléculaire (UMR CNRS 6511), Université de Rennes I, campus de Beaulieu, 35042 Rennes Cedex, France

Corresponding author: maryline.guilloux@univ-rennes1.fr

Received: 8 July 1997
Revised: 21 October 1997
Accepted: 3 November 1997
Published online: 15 February 1998

Abstract

Thin films of have been in-situ deposited by pulsed laser deposition on R-plane on which an epitaxial growth has been achieved for the first time, with the orientation, as shown by X-ray diffraction. The superconducting transition temperature has been determined from DC resistive and AC susceptibility measurements. The critical temperature T_c is typically between 9.5 and 10.3 K and the transitions are narrow: the full width at half maximum of the inductive signal ranges between 0.1 and 0.5 K. The critical current densities have been obtained by standard four probe electrical measurements: in zero field a value larger than has been measured at only 1 K from the end of the transition, and values typically larger than at 4.2 K in an applied magnetic field of 7 T have been observed. The upper critical magnetic field, B_c2, has been determined from the critical current measurements performed at 4.2 K in an applied magnetic field, for two samples. The experimental values of 11 and 12.5 T at 4.2 K are close to those reported on bulk samples (12.5 T). For the first time to our knowledge a surface resistance measurement has been carried out on a Chevrel phase-type compound: a value of 4.5 mΩ at 10 GHz and 4.2 K has been obtained.