Superconducting rare earth transition metal borocarbides

Microscopic changes inHoNi2B2Cdue to thermal treatment and its effect on superconductivity

“…8,[10][11][12] Both superconducting and magnetic properties of HoNi 2 B 2 C strongly depend on its composition within the small but nonnegligible homogeneity range for this quaternary compound. 13 While for flux-grown single crystals only an ordinary superconducting transition at always the same transition temperature has been observed in zero magnetic field, 14,15 there exists a variety of different low-temperature behaviors for polycrystalline samples: a pure superconducting state ͑coexistent with antiferromagnetic order͒, a nonsu-perconducting magnetically ordered state as well as reentrant behavior, governed by the chemical composition within the homogeneity range.…”

Effect of Pt doping on the critical temperature and the upper critical field inYNi2−xPtxB2Cfor doping

“…The quaternary borocarbide superconductor 6 YNi 2 B 2 C displays several unusual properties, namely, large anisotropy in the superconducting order parameter 7,8,9 , a negative curvature 10 in H c2 (T) close to T c and a square flux line lattice 11 at high magnetic fields. In a previous paper 12 , through measurements of ∆ using directional point contact spectroscopy (DPCS) as a function and magnetic field along different crystallographic directions, we have shown that these unusual properties can be understood from a multiband scenario, where large difference in the Fermi velocity on different Fermi sheets 13 gives rise to different electron-phonon coupling strength and different values of ∆. In this paper, we carry out a detailed measurements of H c2 , by applying magnetic field along the two crystallographic in YNi 2-x Pt x B 2 C has to be analyzed beyond single band scenario.…”

Resistivity and electron-phonon coupling in YNi2B2C single crystals

“…The discovery of superconducting quaternary rare-earth borocarbide intermetallic compounds RNi 2 B 2 C (R=rare earth) have aroused great interest because, even though they are layered materials like high-T c cuprates, band-structure calculations predict a three-dimensional electronic structure. Most of the experimental and theoretical results tend to support a conventional BCS-Eliashberg descriptions of the superconducting properties in these materials [1]. Some peculiar features of the upper critical field of YNi 2 B 2 C have been recently explained in the framework of Migdal-Eliashberg theory by considering the presence of two bands, one of them being more deeply involved in the transport properties of the compound [2].…”