Hydrogenation of diamond has been carried out using the electron-cyclotron-resonance microwave plasma chemical-vapor deposition apparatus. According to reflection high-energy and low-energy electron diffraction and X-ray photoelectron spectroscopy measurements, the natural- and synthetic-diamond surfaces maintained their crystallinity even after the hydrogenation. Seebeck effect measurement and the temperature dependence of the resistance revealed an appearance of deep acceptor levels in the hydrogenated diamond layer. The diffusion depth of the hydrogen by the plasma treatment (2 h, 830°C) was roughly estimated to be ∼0.6 µm from the drain current-voltage characteristics of a rudimentary MISFET using the hydrogenated diamond.

We show in this paper that it is possible to induce superconducting vortices in a gold nanowire connected to superconducting electrodes. The gold nanowire acquires superconductivity by the proximity effect. The differential magnetoresistance of the nanowire beyond a critical magnetic field shows uniform oscillations with increasing field with a period of 0 /(2πr 2 ) ( 0 = h/2e is the superconducting flux quantum, r = 35 nm is the radius of the nanowire). Our analysis indicates that these periodic oscillations are the signatures of the sequential generation and moving of vortices across the gold nanowire.

The dielectric properties of SrTiO3 epitaxial film were studied using film grown on oxide superconductor YBa2Cu3O y . They were, to a certain extent, similar to those of the single-crystal bulk in terms of both temperature and electric field dependence, though the value of the dielectric constant was low, particularly at cryogenic temperatures. The observed dielectric properties were analytically expressed. Using the dramatic field dependence of the dielectric constant of the SrTiO3 film in the Au-SrTiO3-YBa2Cu3O y metal-insulator-superconductor (MIS) structure, we determined the work function of (001)YBa2Cu3O y epitaxial film to be ∼6.1 eV.

The surface morphology of both YBa2Cu3O y (YBCO) thin film on a MgO substrate and SrTiO3 (STO) thin film on a YBCO film was observed using scanning tunneling microscopy (STM) and low-energy electron diffraction (LEED) methods. These films were deposited by the ArF excimer laser deposition method. The c-axis-oriented YBCO film of 100 nm thickness grew spirally on a (100)MgO substrate in an island growth mode. The heteroepitaxial STO thin film deposited in situ on the YBCO film grew as if they had filled in the steps of the spiral structure of the YBCO thin film at the stage of initial growth, i.e., STO grew in a kink growth mode. The LEED pattern indicates that the film surface coverd with STO was stable against ordinary air, although the thickness of STO thin film was about 1 nm.

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