µSR investigations of spin-dynamics and magnetism in Triple Perovskites Ba3MRuIrO9 (M = Mg, Na, Zn, Ni)

6H-perovskites with formula Ba3MAA´O9, which form in triple perovskite P63/mmc structure, display interesting magnetic properties on account of large spin-orbit coupling because of the shorter A-A´ distance in this structure. Among these the Ba3MgRuIrO9, Ba3NiRuIrO9, Ba3ZnRuIrO9 and Ba3NaRuIrO9 with mixed 4d (Ru) and 5d (Ir) moments present an interesting magnetic behavior as a result of competing localized and itinerant magnetism. The magnetic susceptibility measurements show a magnetic transition of complex nature near 17 K in Ba3MgRuIrO9, near 88 K in Ba3NaRuIrO9, near 60 K in Ba3NiRuIrO9 and near 75 K in Ba3ZnRuIrO9 with large splitting between ZFC and FC susceptibility. The magnetic measurements show the presence of short-range ferromagnetic and long-range antiferromagnetic correlations in all these compounds and have been suggested to show spin-liquid-like behaviour. Further investigations using the muon spin relaxation (µSR) measurements would be very informative to understand the magnetism and spin-dynamics in Ba3MRuIrO9 (M = Mg, Na, Zn, Ni). We therefore propose to carry out µSR measurements on these compounds using EMU.