Effects of miscut of the SrTiO3 substrate on microstructures of the epitaxial SrRuO3 thin films

We have studied the microstructures of epitaxial SrRuO3 thin films on both exact and miscut (001) SrTiO3 substrates with miscut angle of 1.9° and miscut direction of 12° away from the in-plane [100] axis by transmission electron microscopy (TEM). Among six possible types of domains, the (110) domains [i.e. the (110) planes are parallel to the (001) planes of SrTiO3] are favored during the growth of the SrRuO3 film. The SrRuO3 thin films on exact (001) SrTiO3 are composed of two types of (110) domains in the plane with nearly the same volume fraction. Each type has an in-plane orientation relationship with respect to the substrate of either SrRuO3[1̄10]//SrTiO3[100] and SrRuO3[001]//SrTiO3[010] (the X-type), or SrRuO3[11̄0]//SrTiO3[010] and SrRuO3[001]//SrTiO3[100] (the Y-type). However, the SrRuO3 thin films grown on the miscut (001) SrTiO3 are composed of mainly X-type domain.