Fabrication of GdxFeyOz films using an atomic layer deposition-type approach

Abstract

The growth of complex oxide thin films with atomic precision offers bright prospects to study improved properties and novel functionalities. Here we tackle the fabrication of gadolinium iron oxide thin films by an atomic layer deposition-type approach in which iron and gadolinium tailor-made metalorganic precursors (bis(N-isopropyl ketoiminate)iron(II), [Fe(ⁱpki)₂] and tris(N,N′-diisopropyl-2-dimethylamido-guanidinato)gadolinium(III), [Gd(DPDMG)₃]) are alternately reacted with ozone and deposited on silicon substrates at 250 °C. The structure, chemical composition and magnetic properties of the resulting films are compared with those obtained from a commercially available ferrocene precursor [Fe(Cp)₂] and [Gd(DPDMG)₃]. All films resulted in cation ratio close to nominal stoichiometry with negligible amount of organic species. The tailor-made metalorganic precursors, designed to provide similar thermal behavior, result in the formation of polycrystalline Gd₃Fe₅O₁₂ films coexisting with GdFeO₃, Gd₂O₃ and Fe₂O₃ whereas the combination of [Fe(Cp)₂] and [Gd(DPDMG)₃] mainly favors the formation of Gd₃Fe₅O₁₂ films coexisting with traces of Gd₂O₃. This study demonstrates that this is a viable route to prepare complex Gd_xFe_yO_z films and could be used for the design of complex oxide films with improved properties upon rigorous study of the compatibility of metalorganic precursors.