Strain-dependence of the structure and ferroic properties of epitaxial Ni1 - xTi1 - yO3 thin films grown on sapphire substrates

THIN SOLID FILMS

卷:578

Article

Varga, Tamas¹  Droubay, Timothy C.²  Bowden, Mark E.¹  Stephens, Sean A.¹  Manandhar, Sandeep¹  Shutthanandan, Vaithiyalingam¹  Colby, Robert J.¹  Hu, Dehong¹  Shelton, William A.³  Chambers, Scott A.² 

[1] Environm Mol Sci Lab, Richland, WA USA

[2] Pacific NW Natl Lab, Fundamental & Computat Sci Directorate, Richland, WA 99352 USA

[3] Louisiana State Univ, Baton Rouge, LA 70803 USA

关键词: Epitaxial strain;    Polarization;    Ferromagnetism;    NiTiO3;   

DOI  :  10.1016/j.tsf.2015.02.016

来源: Elsevier

【 摘 要 】

Polarization-induced weak ferromagnetism has been predicted a few years back in compounds MTiO3 (M = Fe, Mn, Ni) (Fennie, 2008). We set out to stabilize this metastable, distorted perovskite structure by growing NiTiO3 epitaxially on sapphire Al2O3 (001) substrate, and to control the polar and magnetic properties via strain. Epitaxial Ni1-xTi1-yO3 films of different Ni/Ti ratios and thicknesses were deposited on Al2O3 substrates by pulsed laser deposition at different temperatures, and characterized using several techniques. The effect of film thickness, deposition temperature, and film stoichiometry on lattice strain, film structure, and physical properties was investigated. Our structural data from x-ray diffraction, electron microscopy, and x-ray absorption spectroscopy shows that substrate-induced strain has a marked effect on the structure and crystalline quality of the films. Physical property measurements reveal a dependence of the Neel transition and lattice polarization on strain, and highlight our ability to control the ferroic properties in NiTiO3 thin films by film stoichiometry and thickness. (C) 2015 Elsevier B.V. All rights reserved.

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