Preparation and Superconducting Properties of MoN_x Thin Films

Abstract

Formation process, phase analysis and superconducting properties of MoNx thin films prepared by DC and RF reactive magnetron sputtering were Investigated. The optical emission spectra of N2 plasma were measured by a spectroscope. In N2 plasma of DC and RF magnetron sputtering, excited N2 molecules, N2 ions and excited Mo atoms were observed. The Tc of cubic MoNx films prepared by DC and RF modes was found to range between 8.5 K and below 4.2 K. B1 like MoN films were nonsuperconducting above 4.2 K in contrast to theoretical predictions.

Phonon and elastic instabilities in MoC and MoN

“…Both of these features are indicative of a potentially high T c , but they are also hallmarks of either structural instabilities that can frustrate the forma-tion of stoichiometric structures, or of magnetic instabilities that can destroy superconductivity. Experimentally, it was found that these features lead instead to structural instabilities in B1 MoN [4][5][6][7][8][9][10] that are manifested by the fact that only highly N deficient or vacancy/defect-rich B1 structures have been made in the laboratory. Alternatively, the more thermodynamically stable hexagonal phase of MoN is often formed close to stoichiometry.…”

The La (Ba2-xLax)Cu3- yOz single crystals : structures and conductivity

“…The structure of these crystals is identical to that of YBa2Cu3 -y07 -Z' with especially a pronounced anisotropy for the heavy atom Debye-Waller factors, Ul, > Un [29]. In addition, Vl/(vi + V2) = 0.393 (7). La(Ba2-.,La,,)CU3-yO6,,,/2-,,, orthorhombic single crystal.…”

An Electron Microscope Study of Defect-free YBa2Cu3O7?x (x » 0.15) with Superconductivity at 93 K

“…Thus, semiconductor grade copper oxides appear to be essential for the production of high quality device material. It is already clear that substitution of yttrium by other rare earths does not significantly affect Tc (Ohshima and Wakiyama 1987), whereas replacement of barium by strontium does not have a positive effect. …”