Josephson tunneling of anisotropic high-Tc d-wave junctions with tilted ab-plane YBa2Cu3O7−y electrodes

H. Arie; K. Yasuda; H. Kobayashi; I. Iguchi; Y. Tanaka; S. Kashiwaya

doi:10.1103/PhysRevB.62.11864

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Josephson tunneling of anisotropic high-Tc d-wave junctions with tilted ab-plane YBa2Cu3O7−y electrodes

H. Arie, K. Yasuda, H. Kobayashi, I. Iguchi, Y. Tanaka, S. Kashiwaya

DOI 10.1103/PhysRevB.62.11864 · Physical Review B

T1

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Abstract

We report measurements on high-Tc YBa2Cu3O7−y (YBCO) Josephson ramp-edge junctions with different ab-plane orientation electrodes relatively rotated by 45°. The ramp-edge junctions with different crystal angles against the interface boundary are fabricated on an MgO(100) substrate using a CeO2 seed-layer technique. The Shapiro steps under microwave irradiation of 9 GHz appear qualitatively different for different crystal angles, which supports the d-wave nature of a YBCO superconductor. The magnetic-field dependence of the Josephson maximum current shows a Fraunhofer-like pattern, which is consistent with the calculated result for the d-wave junctions. The temperature dependencies of the maximum Josephson current for different angle geometry fall off rapidly with increasing temperature and deviate much from the conventional s-wave Ambegaokar-Baratoff prediction. The results are in good qualitative agreement with the calculated results based on the d-wave pairing symmetry taking the presence of the zero energy state into account. The observed angle dependencies clearly indicate that the angle-dependent Josephson current really exists.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
YBa2Cu3O7-y Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown