Magnetic short-range order in the new ternary phase Mn₈Pd ₁₅Si₇

A new compound, Mn₈Pd₁₅Si₇, is reported to crystallize in a face centered cubic unit cell of dimension a = 12.0141(2) Å, space groupFm3̄m, and can thus be classified as a G-phase. The crystal structure was studied by single crystal X-ray diffraction, X-ray and neutron powder diffraction and electron diffraction. A filled Mg ₆Cu₁₆Si₇ type structure was found, corresponding to the Sc₁₁Ir₄ type structure. The magnetic properties were investigated by magnetization measurements and Reverse Monte Carlo modeling of low temperature magnetic short-range order (SRO). Dominating near neighbor antiferromagnetic correlations were found between the Mn atoms and geometric frustration in combination with random magnetic interactions via metal sites with partial Mn occupancy were suggested to hinder formation of long-range magnetic order.