Superconductivity in the TiO and NbO systems
Abstract
This paper presents electrical resistivity and superconductivity studies for the B1 (NaCl) structure oxides of titanium, vanadium, and niobium. In samples of nominal composition TiO_{ x }, VO_{ x }, and NbO_{ x }, x was varied from 0.8 to 1.2. It was found that all three of these oxides exhibit roomtemperature electrical resistivities characteristic of metallic behavior. With decreasing temperature, the resistivity drops steeply in the case of NbO_{ x }, but remains steady or rises somewhat in the case of TiO_{ x } and VO_{ x }, depending on the exact value of x. It is suggested that in TiO_{ x } and VO_{ x } there is a large resistivity component due to scattering of carriers by disordered vacancies. Superconductivity was observed in NbO_{ x }( T _{c}=1.38 K, x=1.0) and TiO_{ x }( T _{c}=1.0 K, x=1.07). In the latter case the material showed a welldefined maximum of T _{c} as a function of composition, with T _{c}<0.05 K for x<0.85 and x>1.20. Several VO_{ x } samples remained normal to 0.07 K.
 Publication:

Journal of Low Temperature Physics
 Pub Date:
 May 1972
 DOI:
 10.1007/BF00660068
 Bibcode:
 1972JLTP....7..291H