Interfacial magnetism in CaRuO3/CaMnO3 superlattices grown on (001) SrTiO3

We have studied epitaxially grown superlattices of CaRuO3/CaMnO3 as well as an alloy film of CaMn0.5Ru0.5O3 on (001) SrTiO3 substrates. In contrast to previous experiments, we have studied CRO/CMO superlattices with a constant CRO thickness and variable CMO thickness. All superlattices exhibit Curie temperatures (T-C) of 110 K. The saturated magnetization per interfacial Mn cation has been found to be 1.1 mu(B)/Mn ion. The T-C's of the superlattices are much lower than the T-C of the alloy film while the saturated magnetization values are larger than that of the alloy film. These observations suggest that interdiffusion alone cannot account for ferromagnetism in the superlattices and that double exchange induced FM must play a role at the interfaces. (c) 2011 American Institute of Physics. [doi: 10.1063/1.3561448]