2003/09/24 by G. A. Ummarino, Arrigo Calzolari, Ummarino, G. A. +13
Physics and Astronomy · #Advanced Condensed Matter Physics #Amplitude #Andreev reflection #Condensed matter physics #Conductance #Crystallite #Cusp (singularity) #Electrical resistivity and conductivity #FOS: Physical sciences #Geometry #Magnetic properties of thin films #Materials science #Optics #Physics #Physics of Superconductivity and Magnetism #Quantum mechanics #Spectroscopy #Superconductivity #Superconductivity (cond-mat.supr-con) #Symmetry (geometry) #cond-mat.supr-con
paper · pdf · doi:10.48550/arxiv.cond-mat/0309553
7 pages, 5 figures, Proceedings of the 6th EUCAS Conference (14-18 September 2003, Sorrento - Italy)- Added acknowledgements
openalex publication_date 2003/09/24 · arxiv created 2003/09/29 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present the results of point-contact spectroscopy measurements in polycrystalline RuSr2GdCu2O8 samples previously characterized from both the structural and the electrical point of view. AC susceptibility and resistivity measurements, as well as SEM and optical microscopy, indicate that the polycrystalline material is made up of small, weakly connected grains. Possibly because of this morphology, point-contact measurements turned out to be rather difficult. Best reproducibility of the conductance curves was achieved in point contacts obtained by pressing Au or Pt-Ir tips on the surface of the samples. The low-temperature conductance curves reproducibly show a clear zero-bias cusp that might be interpreted as due to Andreev reflection at the normal metal-superconductor interface in the case where the superconducting order parameter has a pure d-wave symmetry - even though alternative explanations cannot be ruled out. In this paper we show that these curves can indeed be fitted, in the framework of the generalised BTK model, by using pure d-wave symmetry and a gap of the order of 6 meV. Finally, we present the temperature dependence of the conductance curves from 4.2 K up to the critical temperature of the junctions.