arXiv subjects

Antonio Vecchione

Publications and source records attributed to Antonio Vecchione.

21 records · Page 2Linked to original sources

arXiv2006

Point-Contact Spectroscopy on RuSr2GdCu2O8

We present Point-Contact experiments on polycrystalline RuSr$_2$GdCu$_2$O$_8$ samples. The majority of tunneling curves shows a zero-bias conductance peak, which is modeled by assuming a d-wave pairing symmetry of the superconducting order parameter.The magnetic field dependence of the conductance spectra has been measured in very stable junctions. In some cases, due to the granularity of the samples, clusters of grains in series introduce peculiar features in the conductance spectra.

cond-mat.supr-con↗

arXiv2006

Pairing state in the rutheno-cuprate superconductor RuSr2GdCu2O8: A point contact Andreev Reflection Spectroscopy study

The results of Point Contact Andreev Reflection Spectroscopy on polycrystalline RuSr$_2$GdCu$_2$O$_8$ pellets are presented. The wide variety of the measured spectra are all explained in terms of a modified BTK model considering a \emph{d-wave} symmetry of the superconducting order parameter. Remarkably low values of the energy gap $Δ=(2.8\pm 0.2)meV$ and of the $2Δ/k_BT_c\simeq 2$ ratio are inferred. From the temperature evolution of the $dI/dV$ 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 $H_{c_2}\simeq 30 T$ 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 consequence of the granularity of the sample.

cond-mat.supr-con↗

arXiv2005

Point Contact Study of the Superconducting Order Parameter in RuSr2GdCu2O8

We have performed a detailed study of the conductance characteristics obtained by point contact junctions realized between a normal Pt/Ir tip and syntered RuSr2GdCu2O8 (Ru-1212) samples. Indeed, this compound is subject of great interest due to the coexistence of both magnetic order and bulk superconductivity. In our experiments, the low temperature tunneling spectra reproducibly show a zero bias conductance peak that can be well reproduced by a generalized BTK model in the case of d-wave symmetry of the superconducting order parameter.

cond-mat.supr-con↗