Low-temperature X-ray diffraction, transport properties, specific-heat, thermal expansion and magnetic investigations of SmCu2

A variety of physical properties (low-temperature X-ray diffraction, electrical resistivity, thermal conductivity, thermopower, specific heat, thermal expansion and susceptibility) of orthorhombic SmCu2 have been studied. A significant contribution of the J=5/2 Hund ground state has been observed. An estimation of the overall crystal-field splitting obtained from the termal expansion experiment yields a value of 110 K. The magnetic entropy indicates a doublet ground state, since the observed value (Sm=5.50+or-0.2 J mol-1 K-1) is very near to the theoretical R ln 2. An additional influence of the J=7/2 multiplet is visible in the resistivity and susceptibility results. The pronounced increase of the thermal conductivity in the magnetically ordered region (Neel temperature TN=23 K) is discussed within the framework of magnon-heat conductivity.