Ferromagnetism of epitaxially grown CaRu1−xMxO3 (M=Ti, Mn) films

Epitaxial thin films of CaRu 1− x M x O 3 (M=Ti, Mn) were fabricated on a (0 0 1)-SrTiO 3 substrate by spin-coat method using organometallic solutions (metal alkoxides). Results of X-ray diffraction and transmission electron microscopy indicate that the epitaxial films were grown pseudomorphically so as to align the [0 0 l] axis of the CaRu 1− x M x O 3 films perpendicular to the (0 0 1) plane of the SrTiO 3 substrate. Ferromagnetism and metal–insulator transition are induced by the substitution of transition metal ions. The occurrence of ferromagnetism was explained qualitatively assuming a TiRu 6 cluster model for CaRu 1− x Ti x O 3 film and a mixed valence model for CaRu 1− x Mn x O 3 film. Ferromagnetism was also observed for layered CaRuO 3 /CaMnO 3 film and CaRuO 3 /CaMnO 3 /CaRuO 3 /CaMnO 3 multilayer film and the magnetism was explained by an interfacial exchange interaction model with magnetic Mn 3+ , Mn 4+ , and Ru 5+ ions.