Nonstoichiometry driven ferromagnetism in double perovskite La2Ni1-xMn1+ xO6 insulating thin films

In this work we report on the epitaxial growth of LaNiMnO double perovskite thin films on top of (001) oriented SrTiO substrates by RF magnetron sputtering. The influence of oxygen pressure (P O) and growth temperature on the microstructure, stoichiometry of the films, and magnetic and transport pro...

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Detalles Bibliográficos
Autores: Bernal Salamanca, Mónica Emperatriz, Konstantinovic, Zorica|||0000-0002-6871-7038, Balcells i Argemí, Lluís|||0000-0001-6603-7357, Pannunzio-Miner, Elisa, Sandiumenge Ortiz, Felip|||0000-0003-1336-1529, Lopez-Mir, Laura, Bozzo, Bernat, Herrero-Martín, Javier|||0000-0003-1986-8128, Pomar, Alberto|||0000-0002-5855-2356, Frontera, Carlos|||0000-0002-0091-4756, Martínez, Benjamín|||0000-0001-9879-7748
Tipo de recurso: artículo
Fecha de publicación:2019
País:España
Institución:Universitat Autònoma de Barcelona
Repositorio:Dipòsit Digital de Documents de la UAB
Idioma:inglés
OAI Identifier:oai:ddd.uab.cat:224186
Acceso en línea:https://ddd.uab.cat/record/224186
https://dx.doi.org/urn:doi:10.1021/acs.cgd.8b01897
Access Level:acceso abierto
Palabra clave:Ferromagnetic behaviors
Ferromagnetic orderings
Ferromagnetic properties
High oxygen pressure
Insulating thin films
Magnetic and transport properties
Rf-magnetron sputtering
Superexchange interaction
Descripción
Sumario:In this work we report on the epitaxial growth of LaNiMnO double perovskite thin films on top of (001) oriented SrTiO substrates by RF magnetron sputtering. The influence of oxygen pressure (P O) and growth temperature on the microstructure, stoichiometry of the films, and magnetic and transport properties is thoroughly investigated. It is found that high oxygen pressure promotes the growth of stoichiometric films, with a Ni/Mn ratio almost equal to 1. However, these films exhibit poor ferromagnetic properties with respect to the expected optimum values corresponding to ferromagnetic ordering mediated by superexchange interaction between Mn and Ni according to the Goodenough-Kanamori rules. Most interestingly, films grown at low P O exhibit Ni/Mn ratios below 1, but ferromagnetic properties close to the optimal ones. The valence balance between Ni and Mn ions in nonstoichiometric sample has been elucidated by X-ray absorption spectroscopy. The results indicate that Ni deficiency plays a crucial role in the puzzling insulating ferromagnetic behavior observed in nonstoichiometric samples.

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