Structural, electronic, magnetic, and thermal properties of single-crystalline UNi0.5Sb2

We studied the properties of the antiferromagnetic (AFM) UNi0.5Sb2 (T-N approximate to 161 K) compound in Sb flux-grown single crystals by means of measurements of neutron diffraction, magnetic susceptibility (chi), specific heat (C-p), thermopower (S), thermal conductivity (kappa), linear thermal expansion (Delta L/L), and electrical resistivity (rho) under hydrostatic pressures (P) up to 22 kbar. The neutron diffraction measurements revealed that the compound crystallizes in the tetragonal P4(2)/nmc structure, and the value of the U-moments yielded by the data at 25 K is approximate to 1.85 +/- 0.12 mu(B)/U-ion. In addition to the features in the bulk properties observed at T-N, two other hysteretic features centered near 40 and 85 K were observed in the measurements of chi, S, rho, and Delta L/L. Hydrostatic pressure was found to raise T-N at the rate of approximate to 0.76 K/kbar, while suppressing the two low temperature features. These features are discussed in the context of Fermi surface and hybridization effects.