Crystal growth and magnetic structure of ternary silicide EuPd3Si2

The hexagonal CaCu5-type structure (P6/mmm) is the prototype for more than 100 ternary borides, gallides, and silicides, with general stoichiometry of RTM3X2 (R = lanthanide/alkaline earth; TM = transition metal; X = B, Ga, Si, Ge). We report the synthesis, crystal structure, and bulk magnetic properties of polycrystalline and single crystal samples of EuPd3Si2 and its nonmagnetic analog SrPd3Si2. Both compounds crystallize in the orthorhombic space group symmetry Imma (no. 74, Z = 2, oI 12) displaying pseudohexagonal symmetry. Ferromagnetic (FM) order of Eu2+ at T-C1 = 78 K and a spin-reorientation transition at T-C2 = 5 K appear as distinctive features in bulk magnetization, specific heat, and resistivity/resistance measurements. Neutron powder diffraction measurements on EuPd3Si2 confirm FM order of the Eu2+ spins below T-C1, with the spins aligned along the a axis below T-C2. Electronic band structure calculations corroborate the crystal structure and the FM state for EuPd3Si2, with a Pd d-band polarization in the same direction as the Eu 4 f polarization, enhancing the observed spin moment.