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Transport Properties at Interfaces between Conductive Oxide ReO3 and Cuprate Superconductors

Nobuyuki Iwata ,  Motoshi Masui ,  Akira Muramatsu ,  Hiroshi Yamamoto 

Nihon University, College of Science and Technology, Department of Electronics and Computer Science, 7-24-1, Narashinodai, Funabashi-shi 274-8501, Japan


As well known superconducting transition temperatures Tc's increase as the number of CuO2 planes in the unit cell increases up to n=3, for example in a series of Bi-, Tl-, Hg-based cuprate superconductors (CSC's). However, if sufficient carriers are doped in the CSC's including CuO2 planes above n=4, a higher Tc is expected. It is expected that the higher Tc will be realized at an interface between ReO3 and CSC's. The ReO3 reveals the highest conductivity among oxide materials. As conductive oxides are deposited on the CSC's, a carrier doping takes place adequately from the conductive oxides to CSC's deeply around the interface, specifically taking a role like as a charge reservoir block. In this study we attempt to obtain the highest conductive ReO3 thin film and investigate the transport properties of bi-layer of ReO3 / CSC's.
The Re oxides thin films are prepared by off-axis RF magnetron sputtering. Target is a metal Re disc and a substrate is quartz. The films are grown at ambient substrate temperature for 60min, and then post-annealing in-situ is carried out in Ar or O2 atmosphere for 30min. And also ReO3 thin film is deposited on oxygen-vacant YBa2Cu3O6 (YBCO) and SrCuO2, which were already grown with other deposition equipment.
At annealing temperatures above 200 degree C, cubic ReO3 grew preferentially aligned along the (100) direction. Despite of a large residual resistivity, the resistivity decreased linearly with decreasing temperature. The minimum resistivity was obtained in a film annealed at about 200 degree C and was 4.4×10-5 ohm cm at room temperature. Above 280 degee C rhenium oxides was totally sublimated. The resistivity behavior of both bilayers was roughly similar to that of ReO3 thin film. In this case the interface might be contaminated after exposure to the air. In-situ growth of bilayers will be carried out to develop the resistivity and to show the higher Tc.


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Presentation: poster at E-MRS Fall Meeting 2004, Symposium E, by Nobuyuki Iwata
See On-line Journal of E-MRS Fall Meeting 2004

Submitted: 2004-04-28 09:49
Revised:   2009-06-08 12:55