Superconductivity and magnetism in quaternary borocarbides

Electronic structure, chemical bonding, phase stability, and ground-state properties ofYNi2−x(Co/CRavindran1, Johansson2, Eriksson3 1998Phys. Rev. B41180View full textAdd to dashboardCite

“…Thus, we believe the magnetic correlation effect is not important for the nonappearance of superconductivity in YCo 2 B 2 C. The experimental susceptibility measurements show a Pauli paramagnetic behavior in this material and this is consistent with our result. 58,15 Also, the increase of the cohesive energy ͑Fig. 5͒ and the bulk modulus by an increase of the Co concentration in YNi 2Ϫx Co x B 2 C indicates the stiffening of the lattice.…”

“…3 Considerable excitement was generated by the discovery of superconductivity in a number of such compounds, [4][5][6] and the interplay between superconductivity and magnetism in some of these systems. 7 This class of materials exhibits a variety of phenomena such as fairly high superconducting transition temperature (T c ) in RNi 2 B 2 C (RϭSc,Y,Lu), 1,2,4 coexistence of superconductivity, and magnetism in RNi 2 B 2 C (RϭHo,Er,Tm,Dy), [8][9][10][11]7 with remarkable double reentrant behavior in HoNi 2 B 2 C, 12 magnetic order in RNi 2 B 2 C (RϭNd,Sm,Gd,Tb), [13][14][15] valence fluctuations in CeNi 2 B 2 C ͑Refs. 16,17͒ and UNi 2 B 2 C, 18 heavy fermion behavior in YbNi 2 B 2 C, 19 etc.…”

The suppression of superconductivity in MgCNi3 by Ni-site doping

“…Superconductivity in nickel rich intermetallics is not unprecedented, however. The quaternary borocarbides, RENi 2 B 2 C, are prime examples (2)(3)(4)(5); MgCNi 3 can be considered to be a three dimensional analog of these layered materials. Given the presence of strong antiferromagnetic fluctuations and the suggestion of unconventional pairing in the superconducting state of LuNi 2 B 2 C (6,7), a more detailed study of the properties of MgCNi 3 is of interest.…”

Thermal expansion of single-crystalline HoNi2B2C

“…The Debye temperature used for the fit is 350 K corresponding well to previous data [3]. Towards higher temperatures, obviously the Debye approximation is not valid any more hinting at contributions by optical phonons, as has been realised for non-magnetic borocarbides previously [4]. The parameter D characterising the lattice contribution is found to be 1:4 Â 10 À10 K À4 for both directions.…”

“…Much interest has been focused on HoNi 2 B 2 C because of its comparable values of the transition temperatures of the two ordering phenomena [1]. In the specific heat, a large magnetic contribution was observed [2][3][4][5][6][7]. In comparison, the superconducting phase transition causes only relatively weak changes in the specific heat.…”