SPring-8, the large synchrotron radiation facility

Date: 13:30 April 30(Thu.), 2009

Place: Houkoukan

Speaker: Dr. Ismaldo Bonaldes

Affiliate: Instituto Venezolano de Investigaciones Cientificas

Title: Superconductivity of CePt₃Si and LaPt₃Si without Inversion Symmetry: Analysis by Magnetic Penetration Depth

Abstract:
CePt₃Si remains as the most interesting superconductors without spatial inversion symmetry. Few of the superconducting properties of CePt₃Si are experimentally well substantiated, although not quite understood yet: a constant spin susceptibility in parallel and perpendicular field orientation across Tc, line nodes in the energy gap, and an upper critical magnetic field higher than the weak- coupling Pauli limiting field. Recently, two other intriguing issues have been unmasked in CePt₃Si: the superconducting transition is broad and occurs at two different temperatures depending on the sample or the measuring technique. In this talk I will present a short review on the physics of noncentrosymmetric superconductors and discuss the origin of the line nodes and the broad superconducting transition in CePt₃Si in terms of the results of the magnetic penetration depth of CePt₃Si and isostructural nonmagnetic LaPt₃Si. We will see that parity mixing may not determine the structure of the energy gap in CePt₃Si and CeIrSi₃ and that the broad superconducting transition in CePt₃Si may not be due to impurities/defects. I will also present details of our technique to measure the magnetic penetration depth.

Organizer:
JAEA Shin-ichi Fujimori
PHS: 3914