The Anomaly of Zero-Bias Conductance Peak of the Tunnelling Spectroscopy on the a-Axis Oriented YBa2Cu3O y Epitaxial Films
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We report the directional tunnelling of the normal metal-insulator-superconductor (NIS) planar junctions fabricated on the a-axis oriented YBCO epitaxial thin films at various temperatures and in different applied magnetic fields. The measured spectra show zero-bias conductance peak (ZBCP) and surprisingly, an anomaly of the ZBCP. The observed anomaly is a relatively sharp peak at zero bias voltage on the top of the broader one. We simulate the experimental conductance curves using the OBTK theory, the d-wave scenario, and taking into account the finite quasi-particle life time. The magnetic splitting predicted by the theory was not observed in our experiment at 4.2K even when the magnetic field is applied up to 6T.
KeywordsMagnetic Field Thin Film Magnetic Material Bias Voltage Sharp Peak
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