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TT: Tiefe Temperaturen

TT 16: Postersitzung II: Amorphe und Tunnelsysteme, Mesoskopische Systeme, Schwere Fermionen, Kernmagnetismus

TT 16.47: Poster

Tuesday, March 27, 2001, 14:30–17:00, Rang S\ 3

Properties of strongly diamagnetic YbZn₂Sb₂ — •R. Vollmer¹, C. Pfleiderer¹, M. Uhlarz¹, H. v. Löhneysen^1,2, and A. Nateprov³ — ¹Physikalisches Institut, Universität Karlsruhe — ²Forschungszentrum Karlsruhe, Institut für Festkörperphysik — ³Institute of Applied Physics, Academer 5, MD-2028 Kishniev, Moldova

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 T_N=0.4 K below a strong high temperature Curie-Weiss susceptibility (µ_eff=2.35µ_B). 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 K_α 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.