films

SrRuO­₃ is the metal electrode of choice in complex oxide electronics due to its high room-temperature conductivity, thermal and chemical stability, and close lattice match with several oxide substrates for epitaxial growth. Challenges in the molecular beam epitaxy (MBE) growth of SrRuO₃ thin films arises from the “stubbornness” of Ru, which is difficult to evaporate and to stabilize in the +4 oxidation state. Though electron-beam and ozone-assisted MBE has produced films with low defect densities, this approach raises concerns over flux instabilities. We present a novel solid-source metal-organic MBE approach to supply pre-oxidized Ru by subliming its solid metal-organic precursor in an effusion cell. We demonstrate the growth of phase pure, epitaxial SrRuO₃ on SrTiO₃ (001) and DyScO₃ (110) substrates using high-resolution X-ray diffraction. Combining temperature-dependent electrical transport and magnetometry, we show epitaxial SrRuO₃ on SrTiO₃ (001) with robust ferromagnetism accompanied by an anomalous Hall effect below the Curie temperature of ~150 K. We discuss the effect of cation stoichiometry and epitaxial strain on the crystal structure, surface morphology, electronic and magnetic properties using X-ray spectroscopic techniques.