Structure and superconductivity of vapor quenched Mo and Nb films

Amorphous phases of Mo and Nb which are stable at room temperature have been obtained by e-beam vapor deposition of the metals in a partial N2 atmosphere on substrates kept below 1000K. The structure of these films can be described in terms of the DRPHS model. The amorphous Mo-films show a large increase in the superconducting transition temperature (compared with bulk Mo) while T/sub c/ of amorphous Nb films decreases. For the most homogeneous Mo/sub 1-x/N/sub x/ films the T/sub c/ obtained is near 8.50K and the transition width is less than or approximately equal to 0.10K. In the absence of a nitrogen atmosphere pure Mo-films, vapor quenched onto sputter cleaned substrates at 4.20K are found to be crystalline bcc. Contamination appears to stabilize amorphous or other nonequilibrium crystalline phases