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Title: Anisotropic-strain-relaxation-induced crosshatch morphology in epitaxial SrTiO{sub 3}/NdGaO{sub 3} thin films

Abstract

We investigate the strain relaxation and surface morphology of epitaxial SrTiO{sub 3} (STO) films grown on (001){sub O} and (110){sub O} planes of orthorhombic NdGaO{sub 3} (NGO), and (001) plane of cubic (LaAlO{sub 3}){sub 0.3}(Sr{sub 2}AlTaO{sub 6}){sub 0.7} (LSAT) substrates. Although the average lattice mismatches are similar, strikingly regular crosshatched surface patterns can be found on STO/NGO(001){sub O}[(110){sub O}] films, contrary to the uniform surface of STO/LSAT(001). Based on the orientation and thickness dependent patterns and high-resolution x-ray diffractions, we ascribe the crosshatch morphology to the anisotropic strain relaxation with possibly the 60° misfit dislocation formation and lateral surface step flow in STO/NGO films, while an isotropic strain relaxation in STO/LSAT. Further, we show that the crosshatched STO/NGO(110){sub O} surface could be utilized as a template to modify the magnetotransport properties of epitaxial La{sub 0.6}Ca{sub 0.4}MnO{sub 3} films. This study highlights the crucial role of symmetry mismatch in determining the surface morphology of the perovskite oxide films, in addition to their epitaxial strain states, and offers a different route for designing and fabricating functional perovskite-oxide devices.

Authors:
; ; ; ; ; ;
Publication Date:
OSTI Identifier:
22299613
Resource Type:
Journal Article
Journal Name:
AIP Advances
Additional Journal Information:
Journal Volume: 4; Journal Issue: 10; Other Information: (c) 2014 Author(s); Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 2158-3226
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANISOTROPY; DISLOCATIONS; EPITAXY; LANTHANUM COMPOUNDS; ORTHORHOMBIC LATTICES; OXIDES; PEROVSKITE; STRAINS; STRONTIUM TITANATES; SUBSTRATES; SURFACES; THIN FILMS; X-RAY DIFFRACTION

Citation Formats

Tan, X. L., Chen, F., Chen, P. F., Xu, H. R., Chen, B. B., Jin, F., Gao, G. Y., and Wu, W. B., E-mail: wuwb@ustc.edu.cn. Anisotropic-strain-relaxation-induced crosshatch morphology in epitaxial SrTiO{sub 3}/NdGaO{sub 3} thin films. United States: N. p., 2014. Web. doi:10.1063/1.4897960.
Tan, X. L., Chen, F., Chen, P. F., Xu, H. R., Chen, B. B., Jin, F., Gao, G. Y., & Wu, W. B., E-mail: wuwb@ustc.edu.cn. Anisotropic-strain-relaxation-induced crosshatch morphology in epitaxial SrTiO{sub 3}/NdGaO{sub 3} thin films. United States. doi:10.1063/1.4897960.
Tan, X. L., Chen, F., Chen, P. F., Xu, H. R., Chen, B. B., Jin, F., Gao, G. Y., and Wu, W. B., E-mail: wuwb@ustc.edu.cn. Wed . "Anisotropic-strain-relaxation-induced crosshatch morphology in epitaxial SrTiO{sub 3}/NdGaO{sub 3} thin films". United States. doi:10.1063/1.4897960.
@article{osti_22299613,
title = {Anisotropic-strain-relaxation-induced crosshatch morphology in epitaxial SrTiO{sub 3}/NdGaO{sub 3} thin films},
author = {Tan, X. L. and Chen, F. and Chen, P. F. and Xu, H. R. and Chen, B. B. and Jin, F. and Gao, G. Y. and Wu, W. B., E-mail: wuwb@ustc.edu.cn},
abstractNote = {We investigate the strain relaxation and surface morphology of epitaxial SrTiO{sub 3} (STO) films grown on (001){sub O} and (110){sub O} planes of orthorhombic NdGaO{sub 3} (NGO), and (001) plane of cubic (LaAlO{sub 3}){sub 0.3}(Sr{sub 2}AlTaO{sub 6}){sub 0.7} (LSAT) substrates. Although the average lattice mismatches are similar, strikingly regular crosshatched surface patterns can be found on STO/NGO(001){sub O}[(110){sub O}] films, contrary to the uniform surface of STO/LSAT(001). Based on the orientation and thickness dependent patterns and high-resolution x-ray diffractions, we ascribe the crosshatch morphology to the anisotropic strain relaxation with possibly the 60° misfit dislocation formation and lateral surface step flow in STO/NGO films, while an isotropic strain relaxation in STO/LSAT. Further, we show that the crosshatched STO/NGO(110){sub O} surface could be utilized as a template to modify the magnetotransport properties of epitaxial La{sub 0.6}Ca{sub 0.4}MnO{sub 3} films. This study highlights the crucial role of symmetry mismatch in determining the surface morphology of the perovskite oxide films, in addition to their epitaxial strain states, and offers a different route for designing and fabricating functional perovskite-oxide devices.},
doi = {10.1063/1.4897960},
journal = {AIP Advances},
issn = {2158-3226},
number = 10,
volume = 4,
place = {United States},
year = {2014},
month = {10}
}