Possible nucleation of a 2D superconducting phase on WO3 single crystals surface doped with Na+
Department of Materials and Interfaces, The Weizmann Institute of Science, Rehovot
Published online: 15 May 1999
WO3 crystals with a surface composition of Na0.05WO3 were grown. These crystals exhibit a sharp diamagnetic step in magnetization at 91 K, and a magnetic hysteresis below this temperature. As the temperature is lowered below 100 K in transport measurements, a sharp metal to insulator transition is observed, this is followed by a sharp decrease in the resistivity when the temperature is lowered to about 90 K. When the surface of the crystals was covered by gold the depth of the diamagnetic step had decreased considerably. These results indicate a possible nucleation of a superconducting phase on the surface of these crystals. This is a non cuprate system exhibiting a critical temperature in the HTS range.
PACS: 74.70.-b – Superconducting materials (excluding high-Tc compounds) / 74.20.-z – Theories and models of superconducting state / 74.60.Ec – Mixed state, critical fields, and surface sheath
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1999