Thickness-Dependent Structure-Property Relationships in Strained (110) SrRuO_3 Thin Films

摘要

Thickness-dependent structure-property relationships in strained SrRuO_3 thin films on CdScO_3 (CSO) substrates are reported. The film is found to have epitaxially stabilized crystal structures that vary with the film thickness. Below 16 nm, the √2a_(pc) ×√2a_(pc) × 2a_(pc) monoclinic structure is stabilized while above 16 nm the film has the a_(pc) ×2a_(pc)×a_(pc) tetragonal structure. The thickness-dependent structural changes are ascribed to the substrate-induced modification in the RuO_6 octahedral rotation pattern, which highlights the significance of the octahedral rotations for the epitaxial strain accommodation in the coherently-grown films. Close relationships between the structural and physical properties of the films are also found. The monoclinic film has the uniaxial magnetic easy axis 45° away from the [110]_(GSO) direction while the tetragonal film has the one that lies along the in-plane [1-10]_(GSO) direction. The results demonstrate that the octahedral rotations in the strained per-ovskite oxide thin films are a key factor for determining their structure phases and physical properties.