Anisotropic transport and magnetic properties of ternary uranium antimonides U3ScSb5 and U3TiSb5

作者：Mar Arthur^*; Tougait Olivier; Potel Michel; Noel Henri; Lopes Elsa B

来源：Chemistry of Materials, 2006, 18(18): 4533-4540.

DOI：10.1021/cm061281y

Single needle-shaped crystals of U3ScSb5 and U3TiSb5 were grown in a tin flux. The structure of the new compound U3ScSb5 was determined from single-crystal X-ray diffraction data (Pearson symbol hP18, hexagonal, space group P6(3)/mcm, Z = 2, a = 9.2145(2) angstrom, c = 6.1938(2) angstrom). The angular dependence of the magnetization has been studied. Ferromagnetic ordering develops within the ab plane at T-C = 130 K for U3ScSb5 and 160 K for U3TiSb5, but there are essentially no magnetic interactions parallel to the c axis, confirming the high anisotropy expected from the crystal structure. In both cases, the easy axis for magnetization is the [120] direction. A sharp decrease below the ordering temperature is observed in the electrical resistivity parallel to the c axis; in contrast, the temperature dependence is much weaker within the ab plane. For U3TiSb5, a second transition occurs at 25 K, possibly arising from a spin reorientation process. The thermoelectric power measured along the c axis for both compounds is positive and small at high temperatures, following approximately a linear dependence with temperature indicative of metallic behavior in this region. The thermopower exhibits a kink at the ferromagnetic transition temperature in the case of U3TiSb5, but it is not so clear in the case of U3ScSb5. A change in sign of the thermopower occurs below TC for both compounds, characteristic of multiband conducting systems.

• 出版日期2006-9-5