Temperature dependence of the structural parameters of the non-oxide perovskite superconductor MgCNi3

We report the structural parameters of superconducting MgCxNi3 (x = 0.96, T -c = 7.3 K) as a function of temperature, from 2 to 295 K, determined by ne utron powder diffraction profile refinement. The compound has the perovskit e structure over the whole temperature range, with symmetry Pm (3) over bar m and a = 3.81221(5) Angstrom at 295 K: no structural or long range magneti c ordering transitions were observed. The lattice parameter a and tho Debye -Waller factors for the individual atoms decrease smoothly with decreasing temperature. There are no unusual changes of the structural parameters near T-c. (C) 2001 Elsevier Science B.V. All rights reserved.