Epitaxial A-Site Ordered Perovskite Manganite SmBaMn2O6 Film on SrTiO3(001):  Fabrication, Structure, and Physical Property

An A-site ordered perovskite manganite SmBaMn2O6 - δ film was fabricated by means of an excimer laser-assisted metal−organic deposition (ELAMOD) and epitaxially grown on a SrTiO3(001) substrate. The SmBaMn2O6 - δ film was crystallized in [010]- and [001]-oriented domains that were confirmed by X-ray diffraction and cross-section transmittance electron microscopy (TEM). The A-site ordered structure formed at 500 °C under KrF laser irradiation at a laser fluence of 140 mJ/cm2 for 60 min in an Ar flow, whereas disordered A-site cations formed under laser irradiation at fluences less than 120 mJ/cm2 and/or in an oxygen atmosphere. A SmBaMn2O6 film was obtained by oxygen annealing of the as-prepared SmBaMn2O6 - δ film at 500 °C for 3 h. The effects of structural strain due to the substrate on the physical properties of the SmBaMn2O6 film are discussed in terms of the results of structural analysis and electrical resistivity data. The electrical resistivity for the SmBaMn2O6 film on SrTiO3(001) show insulating behavior without a first-order charge/orbital order (CO) transition caused by constraint of lattice change associated with the CO because of the undeformable substrate lattice. The ELAMOD process is expected to serve as a new key technique for the fabrication of A-site ordered perovskite manganite thin films.