Andreev-reflection and Point-Contact Spectroscopy of Superconducting Rare Earth Transition Metal Borocarbides
Abstract
Description
The superconducting energy gap and quasiparticle density of states (DOS) is measured by means of Andreev-reflection spectroscopy in normal metal - superconductor point contacts. It is found that both in paramagnetic and in antiferromagnetically ordered states (Tm- and Dy-compounds) the DOS has the BCS-like form while in Er- the dip in the temperature dependence of the gap is observed at the Neel temperature. In Ho-compound, the non-BCS-like form of DOS is observed in the temperature region where the incommensurate spin density waves exist along the axes a and c .
Inelastic point-contact spectroscopy performed on these compounds shows that the low-frequency phonons are important for the superconducting state which are strongly mixed with the magnetic excitation branches in magnetic superconductors.
11 pages, 8 figures Invited talk presented at the NATO_ARW "Rare Earth Transition Metal Borocarbides (Nitrides): Superconducting, Magnetic and Normal State Properties", 14-17 June 2000, Dresden, Germany
11 pages, 8 figures Invited talk presented at the NATO_ARW "Rare Earth Transition Metal Borocarbides (Nitrides): Superconducting, Magnetic and Normal State Properties", 14-17 June 2000, Dresden, Germany