Li Hong-Cheng

SUPERCONDUCTIVITY MECHANISM OF HIGH-TC OXIDES

Abstract The superconductivity mechanism of high Tc oxides is proposed. Based on the theory of strong-coupling superconductivity, we deduce a Tc formula for supersconducting oxides: Tc=0.15 (N(E F )Vd 2 /N′M) 1 2 Ba) h /K B Applying this formula to the SrxLa2−xCuO4−y system, we find good consistency between the theory and experiment results. We analyze the basic factors which affect Tc of these oxides further and claim a possibility of RT superconductivity within the framework of BCS theory.

The effect of temperature on ion beam mixing of Mo films on Si substrates

Abstract The atomic mixing of Mo/Si samples irradiated by 170 keV Ar + or Xe 2+ ions has been investigated by backscattering spectrometry. The Mo films of 550 A in thickness deposited on (111) Si substrates were irradiated at temperatures from −196 up to 350°C with different beam fluxes and different doses. The silicides of both MoSi 2 and Mo 5 Si 3 were observed at 150 and 250°C, but only MoSi 2 was observed at 350°C. These results suggest that the radiation induced reaction at Mo/Si interfaces at high temperature is dominated by the interstitial migration of Si atoms in the intro-cascade regions, rather than long range migrations of defects and thermal spike effects.