A study of the new cubic, ordered perovskites BaLa MRuO 6 ( M = Mg, Fe, Co, Ni, or Zn) and the related phases La 2MRuO 6 ( M = Mg, Co, Ni, or Zn) by 99Ru Mössbauer spectroscopy and other techniques

⁵⁷Fe and ⁹⁹Ru Mössbauer spectroscopy, coupled with magnetic susceptibility measurements down to 4.2 K, have been used to study the electronic and magnetic properties of the new cubic-ordered perovskites BaLa MRuO ₆ ( M = Mg, Fe, Co, Ni, or Zn). The ruthenium is present in the +5 oxidation state in all the compounds except BaLaFeRuO ₆ which contains iron(III) and ruthenium(IV). All the compounds exhibit long-range antiferromagnetic order, with Néel temperatures in the range 20-40 K. Mössbauer spectra for the new compound La ₂CoRuO ₆ and the isostructural cubic perovskites La ₂MRuO ₆ ( M = Mg, Ni, or Zn) confirm the presence of ruthenium(IV) in these phases and indicate that they are not ordered magnetically at 4.2 K.