Nonstoichiometry driven ferromagnetism in double perovskite La2Ni1-xMn1+ xO6 insulating thin films
Bernal Salamanca, Mónica Emperatriz (Institut de Ciència de Materials de Barcelona)
Konstantinovic, Zorica (University of Belgrade. Center for Solid State Physics and New Materials)
Balcells Argemí, Lluís (Institut de Ciència de Materials de Barcelona)
Pannunzio-Miner, Elisa (Institut de Ciència de Materials de Barcelona)
Sandiumenge Ortiz, Felip (Institut de Ciència de Materials de Barcelona)
Lopez-Mir, Laura (Institut de Ciència de Materials de Barcelona)
Bozzo, Bernat (Institut de Ciència de Materials de Barcelona)
Herrero-Martín, Javier (ALBA Laboratori de Llum de Sincrotró)
Pomar, Alberto (Institut de Ciència de Materials de Barcelona)
Frontera, Carlos (Institut de Ciència de Materials de Barcelona)
Martínez, Benjamín (Institut de Ciència de Materials de Barcelona)

Date:	2019
Abstract:	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.
Grants:	Ministerio de Economía y Competitividad SEV-2015-0496 Ministerio de Economía y Competitividad MAT2015-71664-R European Commission 645658
Note:	This is an open access article published under an ACS AuthorChoice License. See Standard ACS AuthorChoice/Editors' Choice Usage Agreement
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Ferromagnetic behaviors ; Ferromagnetic orderings ; Ferromagnetic properties ; High oxygen pressure ; Insulating thin films ; Magnetic and transport properties ; Rf-magnetron sputtering ; Superexchange interaction
Published in:	Crystal Growth and Design, Vol. 19, issue 5 (May 2019) , p. 2765-2771, ISSN 1528-7505

DOI: 10.1021/acs.cgd.8b01897

7 p, 3.1 MB

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