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Type: 
Journal
Description: 
The results of point contact Andreev reflection spectroscopy on polycrystalline Ru Sr 2 Gd Cu 2 O 8 pellets are presented. The wide variety of the measured spectra are all explained in terms of a modified Blonder–Tinkham–Klapwijk model considering a d-wave symmetry of the superconducting order parameter. Remarkably low values of the energy gap Δ=(2.8±0.2) meV and of the 2 Δ∕ k B T c≃ 2 ratio are inferred. From the temperature evolution of the d I∕ d V vs V characteristics we extract a sublinear temperature dependence of the superconducting energy gap. The magnetic field dependence of the conductance spectra at low temperatures is also reported. From the Δ vs H evolution, a critical magnetic field H c 2≃ 30 T is inferred. To properly explain the curves showing gap-like features at higher voltages, we consider the formation of a Josephson junction in series with the point contact junction, as a …
Publisher: 
American Physical Society
Publication date: 
21 Feb 2006
Authors: 

Samanta Piano, Fabrizio Bobba, Filippo Giubileo, Anna Maria Cucolo, Marcello Gombos, Antonio Vecchione

Biblio References: 
Volume: 73 Issue: 6 Pages: 064514
Origin: 
Physical Review B