Synthesis, structure, and magnetoresistance of SmPd2Ga2

Single crystals of a new ternary compound, SmPd(2)Ga(2), have been synthesized by flux growth methods. This compound adopts a tetragonal space group I4/mmm, Z = 2, with lattice parameters a = 4.2170(3) A and c = 10.4140(3) A. The crystal structure is composed of layers of isolated Sm atoms and layers of PdGa(4) edge-sharing tetrahedra alternating along the c-axis. The sample is metallic (d rho/dT > 0) with a weak temperature dependence above 100 K. This new material has physical properties similar to those of other Sm intermetallics and has, most notably, a large positive magnetoresistance at low temperatures. Magnetic measurements indicate that SmPd(2)Ga(2) is ferromagnetic with T(c) approximately 5 K.