Structural studies with TbNi2B2C single crystals and TbxY(1−x)Ni2B2C polycrystals

Rare-earth metal transition metal borocarbide and nitridoborate superconductors

“…The same trends were found in neutron powder diffraction studies down to temperatures of 1.6 K, however, the minimum of c was only pointed out for Y [14,131]. For R ¼ Dy and Tb neither the (B--Ni--B) angles nor the free parameter z(B) show a significant temperature dependence over the investigated temperature range [44,45]. A detailed low-temperature study on YNi 2 [B 2 C] in the temperature range of 25-300 K, however, revealed a significant trend in the z(B) parameter resulting in an increasing bond length d(B--C) within the borocarbide ion with increasing temperature and a concomitant decrease of the distance d(Ni--B) [106].…”

“…Temperature dependent X-ray diffraction on members of the Ni series reveal a monotonic increase of the lattice parameter a and the volume V with increasing temperature and similar a monotonic decrease in c/a between 90 and 300 K. However, the c lattice parameter displays a minimum at around 220 K, which for R ¼ Tb is most pronounced [44,45,106]. The same trends were found in neutron powder diffraction studies down to temperatures of 1.6 K, however, the minimum of c was only pointed out for Y [14,131].…”

“…For most compounds RNi 2 [B 2 C] a flux technique using Ni 2 B as solvent was successful for growth of single crystals with plate-like shape and the crystallographic c-axis perpendicular to the plate surface [42][43][44][45][46][47][48]. This flux is regarded as especially well suited for growth 356 R. Niewa, L. Shlyk, B. Blaschkowski (2) 754.86 (6) 754.6(1) 754.4…”

Assessing free lattice and structure parameters from the atomic level

“…Apart from various earlier X‐ray structure refinements of selected compounds to supplement data sets provided by databases (for the methods applied cf., e.g. Refs …”

“…Refs. 11,12), the present communication is based on calculating interatomic distances d, normalized with respect to the lattice parameter a, as function of free parameters p from nearest neighbours on to about neighbours one lattice parameter apart. Through data mining of inorganic structures, dealing with members of the same structure type separately, frequently occurring parameter values can be related to intersection points d j (p i ) = d k (p i ) , (j, k = 1 .…”