Growth and characterization of Va-Sn-Ga (Va = Ta, Nb, V) superconducting compounds

A systematic study of Va-Sn-Ga (Va = Ta, Nb, V) ternary systems has been made from the point of view of crystal growth, crystal structure and physical properties. Applying the self-component flux method where molten tin acted as a solvent, single crystals of new ternary intermetallic compounds Ta5SnGa2, Nb5Sn2Ga and V5Sn5Ga3, were successfully synthesized. The crystal structures of Ta5SnGa2 and Nb5Sn2Ga are very similar each other: both of them belong to the tetragonal system (space group: 14/mcm) and are isostructural with W5Si3. In contrast to them, V5Sn5Ga3, is orthorhombic (space group: Acam) and crystallizes in a new structural type. Superconducting transitions have been observed in Ta5SnGa2 and Nb5Sn2Ga crystals at 1.80 and 1.75 K.