Institution: | a Departamento de Química, Instituto Tecnológico e Nuclear, P-2686-953, Sacavém, Portugal b Departamento de Física, Faculdade de Ciências da Universidade de Lisboa, Campo Grande ed. C1, P-1700, Lisboa, Portugal c Departamento de Física, Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, P2825-114, Monte de Caparica, Portugal d Laboratoire de Chimie du Solide et Inorganique Moléculaire, UMR CNRS 6511, Université de Rennes 1, Avenue de Général Leclerc, F-35042, Rennes, France |
Abstract: | Millimetre-size UFe5Sn single crystals were grown by the top seed solution growth method and characterized by magnetization, 57Fe Mössbauer spectroscopy and specific heat measurements in order to study the magnetic transitions detected in powder samples at 248 and 178 K. The magnetization measurements show different behaviour along the three crystallographic directions but with similar values of spontaneous magnetization along a and c. The transition at 248 K is associated with ferromagnetic ordering of iron moments along the c-axis, while the transition at lower temperature is associated with a reorientation towards b. Mössbauer data show that this reorientation is concomitant to the ordering of the Fe2 sites, which in a large proportion remain paramagnetic between the two transition temperatures. Specific heat measurements are consistent with the establishment of magnetic ordering at 248 K, followed by a spin reorientation at 178 K, yielding γ(0 K) 140 mJ/(mol K2) and θ 290 K for UFe5Sn. |