Antiferromagnetic ordering with an anisotropy reversal in USn0.5Sb1.5USn0.5Sb1.5

We report on single crystal growth, crystal structure refinements and on the measurements of low-temperature magnetic properties of a novel uranium intermetallic USn0.5Sb1.5. Single crystals were grown by means of the antimony flux technique. The crystal structure, refined from single crystal X-ray data, appears to be similar to that of USb2, i.e., the tetragonal, anti-Cu2Sb type unit cell with space group P4/nmm  . Magnetisation and electrical resistivity measurements revealed that this compound orders antiferromagnetically below TN=177(1)K. A large magnetocrystalline anisotropy observed in the magnetic properties of USn0.5Sb1.5 changes dramatically with decreasing temperature, switching from an easy magnetisation c-axis to an easy ab-plane at 163 K. Due to the opening a superzone gap, the electrical resistivity in-plane shows a small hump just below TNTN in a manner resembling the formation of spin-density wave or/and charge-density wave.

(a) Temperature dependence of the reciprocal magnetic susceptibility of USn0.5Sb1.5 measured perpendicular to the cc-axis (χ⊥)(χ⊥) and along the cc-axis (χ∥)(χ∥). (b) Magnetic susceptibility as a function of temperature below 400 K.Figure optionsDownload as PowerPoint slide