Strong Dependence of Oxygen Octahedral Distortions in SrRuO3 Films on Types of Substrate-Induced Epitaxial Strain

• Published in: Crystal growth & design Vol. 14; no. 12; pp. 6478 - 6485
• Main Authors: Aso, Ryotaro, Kan, Daisuke, Fujiyoshi, Yoshifumi, Shimakawa, Yuichi, Kurata, Hiroki
• Format: Journal Article
• Language: English
• Published: Washington,DC American Chemical Society 03.12.2014
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Magnetic properties and materials; Magnetotransport phenomena, materials for magnetotransport; Physics; Structure and morphology; thickness; Structure of solids and liquids; crystallography; Structure of specific crystalline solids; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; Epitaxial layers; Transport properties; Tetragonal lattices; Epitaxy; Distortion; Monoclinic lattices; Layer thickness; Physical properties; Thin films; Tensile stress; Magnetic anisotropy; Size effect; Stress effects; Magnetoresistance; Scanning transmission electron microscopy; Crystal structure
• ISSN: 1528-7483; 1528-7505
• DOI: 10.1021/cg501340e

This work investigates the effects of types of epitaxial strain on the structural and magneto-transport properties of SrRuO3 (SRO) thin films grown on (110)ortho NdGaO3 (NGO) and (110)ortho SmScO3 (SSO) substrates that result in a −1.66% compressive strain and a +1.63% tensile strain, respectively. Although the epitaxial strains induced by the NGO and SSO substrates are almost equal in magnitude, the film properties were found to be strongly dependent on the type of strain. High-resolution scanning transmission electron microscopy revealed that the compressively strained SRO films possess a tetragonal structure with no octahedral tilts, while the tensilely strained SRO films undergo a thickness-dependent transition from a monoclinic structure with octahedral tilts to a tetragonal structure with small tilts. These findings indicate that octahedral tilt propagation from the substrate into the film is preferentially induced under tensile rather than compressive strain. We further found that the magneto-transport properties of SRO films exhibit a significant dependence on the type of the epitaxial strain, demonstrating the close correlation between strain-induced octahedral distortions and magnetic anisotropy. These results highlight the important role of the type of the epitaxial strain on the structural and physical properties of epitaxial thin films.