Evidence of a minority monoclinic LaNiO2.5phase in lanthanum nickelate thin films.
LaNiO3(LNO) thin films of 14 nm and 35 nm thicknesses grown epitaxially on LaAlO3(LAO) and (LaAlO3)0.3(Sr2TaAlO6)0.7(LSAT) substrates are studied using High Resolution Transmission Electron Microscopy (HRTEM) and High Angle Annular Dark Field (HAADF) imaging. The strain state of the films is studied using Geometric Phase Analysis (GPA). Results show the successful in-plane adaptation of the films to the substrates, both in the compressive (LAO) and tensile (LSAT) cases. Through the systematic analysis of HRTEM superstructure contrast modulation along different crystal orientations, localized regions of the monoclinic LaNiO2.5phase are detected in the 35 nm films.
Laboratory of Electron Nanoscopy (LENS-MIND-IN2UB), Institute of Nanoscience and Nanotechnology, Electronics Department, University of Barcelona, c/ Martí i Franqués 1, Barcelona 08028, Catalonia, Spain. llopez@el.ub.edu.
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http://orcid.org/0000-0003-1456-079X
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López-Conesa
Laboratory of Electron Nanoscopy (LENS-MIND-IN2UB), Institute of Nanoscience and Nanotechnology, Electronics Department, University of Barcelona, c/ Martí i Franqués 1, Barcelona 08028, Catalonia, Spain. llopez@el.ub.edu and Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra 08193, Catalonia, Spain and Centres Científics i Tecnològics de la Universitat de Barcelona (CCiT-UB), c/Lluís Solé i Sabarís s/n, Barcelona 08028, Catalonia, Spain.
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Rebled
Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra 08193, Catalonia, Spain.
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Pesquera
Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra 08193, Catalonia, Spain.
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Dix
Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra 08193, Catalonia, Spain.
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Sánchez
Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra 08193, Catalonia, Spain.
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Herranz
Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra 08193, Catalonia, Spain.
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Fontcuberta
Laboratorio de Microscopías Avanzadas (LMA) - Instituto de Nanociencia de Aragón (INA) and Departamento de Física de la Materia Condensada, Universidad de Zaragoza, Zaragoza 50018, Spain and Fundación ARAID, Zaragoza 50018, Spain.
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Magén
Centre d'Élaboration des Matériaux et d'Etudes Structurales (CEMES-CNRS), 29 rue Jeanne Marvig, BP 94347, 31055 Toulouse Cedex 4, France.
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Casanove
Laboratory of Electron Nanoscopy (LENS-MIND-IN2UB), Institute of Nanoscience and Nanotechnology, Electronics Department, University of Barcelona, c/ Martí i Franqués 1, Barcelona 08028, Catalonia, Spain. llopez@el.ub.edu.
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Estradé
Laboratory of Electron Nanoscopy (LENS-MIND-IN2UB), Institute of Nanoscience and Nanotechnology, Electronics Department, University of Barcelona, c/ Martí i Franqués 1, Barcelona 08028, Catalonia, Spain. llopez@el.ub.edu.
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Peiró