Focused ion beam induced deposition of superconducting thin films

Superconducting thin films have been deposited using gallium focused ion beam with tungsten carboxyl W(CO)6 as precursor. The composition of the films is investigated by electron probe microanalysis (EPMA), which shows atomic concentrations of about 40%, 40%, and 20% of tungsten, carbon, and gallium, respectively. From resistivity and magnetic measurements, the superconducting critical temperature is 5.2 K. Furthermore, the upper critical fields and coherence length, are deduced from resistivity data measured at different applied magnetic fields, and have zero Kelvin values of 9.5 T and 5.9 nm, respectively. This technique can be used as a template-free fabrication method for superconducting circuits and devices. (c) 2005 Elsevier B.V. All rights reserved.