•R. Vollmer1, C. Pfleiderer1, M. Uhlarz1,
H. v. Löhneysen1,2 und A. Nateprov3
2Forschungszentrum Karlsruhe, Institut für Festkörperphysik
3Institute of Applied Physics, Academer 5, MD-2028 Kishniev,
Moldova
1Physikalisches Institut, Universität Karlsruhe
The f13 electronic configuration of elementary Yb suggests
formally an electron-hole analogy of Yb-based intermetallic compounds with
Ce-based materials. Contrary to Ce-based materials the application of pressure
is expected to drive intermediate-valent Yb-based compounds towards antiferromagnetic
ordering. In semi-metallic YbZn2As2 antiferromagnetic
order was previously reported at TN = 0.4 K below a strong high
temperature Curie-Weiss susceptibility (meff
= 2.35mB). Single-crystal samples
of YbZn2Sb2 have been prepared by sintering high-purity
starting materials in a carbon-glass crucible at 1200°
C. The structure was determined by Cu Ka
powder diffraction and found to be the same as for YbZn2As2
(P3m1) with a lattice constant increased by 6.3%. Resistivity, magnetisation
and specific heat have been measured at low T and high magnetic field to
characterise the properties of YbZn2Sb2. In contrast
to expectation YbZn2Sb2 is, however, not intermediate
valent, but is a strongly diamagnetic semi-metal, where the diamagnetism
exceeds Larmor elemental contributions by more than three orders of magnitude.