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

In this work we report on the epitaxial growth of La2NiMnO6 double perovskite thin films on top of (001) oriented SrTiO3 substrates by RF magnetron sputtering. The influence of oxygen pressure (P O2) and growth temperature on the microstructure, stoichiometry of the films, and magnetic and transport...

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Detalles Bibliográficos
Autores: Bernal-Salamanca, Monica, Konstantinovic, Zorica, Balcells, Lluis, Pannunzio Miner, Elisa Victoria, Sandiumenge, Felip, Lopez Miranda, Laura Ines, Bozzo, Bernat, Herrero Martín, Javier, Pomares, Miguel Alberto, Frontera, Carlos, Martínez, Benjamín
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2019
País:Argentina
Institución:Consejo Nacional de Investigaciones Científicas y Técnicas
Repositorio:CONICET Digital (CONICET)
Idioma:inglés
OAI Identifier:oai:ri.conicet.gov.ar:11336/120043
Acceso en línea:http://hdl.handle.net/11336/120043
Access Level:acceso abierto
Palabra clave:Thin films
Ions
Oxygen
Magnetic properties
Transition metals
https://purl.org/becyt/ford/1.4
https://purl.org/becyt/ford/1
Descripción
Sumario:In this work we report on the epitaxial growth of La2NiMnO6 double perovskite thin films on top of (001) oriented SrTiO3 substrates by RF magnetron sputtering. The influence of oxygen pressure (P O2) 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 Mn4+ and Ni2+ according to the Goodenough-Kanamori rules. Most interestingly, films grown at low P O2 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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