Synthesis and properties of epitaxial thin films of c-axis oriented metastable four-layered hexagonal BaRuO3

We have grown epitaxial thin films of c-axis oriented metastable four-layered hexagonal BaRuO3 on a (111) SrTiO3 substrate by 90 degrees off-axis sputtering techniques. X-ray diffraction and transmission electron microscopy reveal that the films are single domains of c-axis four-layered hexagonal structures with an in-plane epitaxial arrangement of BaRuO3 {[}0]parallel to SrTiO3{[}110]. Surfaces with smooth terraces having a step height of a half unit cell (similar to 4.7 Angstrom) have been observed by scanning tunneling microscopy. The in-plane electrical resistivity of the films is metallic, with a room temperature value of 810 mu Omega cm and slightly curved temperature dependence. Their magnetic susceptibility is Pauli paramagnetic. The metastable layered metallic oxide can be used for understanding new solid-state phenomena and device applications. (C) 2000 American Institute of Physics. {[}S0003-6951(00)00228-X].