  We investigate structural and transport properties of highly Ru-deficient
SrRu0.7O3 thin films prepared by molecular beam epitaxy on (001) SrTiO3
substrates. To distinguish the influence of the two types of disorders in the
films, Ru vacancies within lattices and disorders near the interface, SrRu0.7O3
thin films with various thicknesses (t = 1-60 nm) were prepared. It was found
that the influence of the former dominates the electrical and magnetic
properties when t > 5-10 nm, while that of the latter does when t < 5-10 nm.
Structural characterizations revealed that the crystallinity, in terms of the
Sr and O sublattices, of SrRu0.7O3 thin films, is as high as that of the
ultrahigh-quality SrRuO3 ones. The Curie temperature (TC) analysis elucidated
that SrRu0.7O3 (TC = 140 K) is a material distinct from SrRuO3 (TC = 150 K).
Despite the large Ru deficiency (30%), the SrRu0.7O3 films showed metallic
conduction when t > 5 nm. In high-field magnetoresistance measurements, the
fascinating phenomenon of Weyl fermion transport was not observed for the
SrRu0.7O3 thin films irrespective of thickness, which is in contrast to the
stoichiometric SrRuO3 films. The (magneto)transport properties suggest that a
picture of carrier scattering due to the Ru vacancies is appropriate for
SrRu0.7O3, and also that proper stoichiometry control is a prerequisite to
utilizing the full potential of SrRuO3 as a magnetic Weyl semimetal and
two-dimensional spin-polarized system. Nevertheless, the large tolerance in Ru
composition (30 %) to metallic conduction is advantageous for some practical
applications where SrRu1-xO3 is exploited as an epitaxial conducting layer.
