Biskup Zaja, NevenkoSalafranca, JuanMehta, ViratOxley, Marrk P.Suzuki, YuriPennycook, Stephen J.Pantelides, Sokrates T.Varela Del Arco, María2023-12-192023-12-192014Biškup, N., Salafranca, J., Mehta, V., Oxley, M. P., Suzuki, Y., Pennycook, S. J., ... & Varela, M. (2014). Insulating ferromagnetic LaCoO 3− δ films: A phase induced by ordering of oxygen vacancies. Physical Review Letters, 112(8), 087202.0031-900710.1103/PhysRevLett.112.087202https://hdl.handle.net/20.500.14352/91493The origin of ferromagnetism in strained epitaxial LaCoO_(3) films has been a long-standing mystery. Here, we combine atomically resolved Z-contrast imaging, electron-energy-loss spectroscopy, and density-functional calculations to demonstrate that, in epitaxial LaCoO_(3) films, oxygen-vacancy superstructures release strain, control the film’s electronic properties, and produce the observed ferromagnetism via the excess electrons in the Co d states. Although oxygen vacancies typically dope a material n-type, we find that ordered vacancies induce Peierls-like minigaps which, combined with strain relaxation, trigger a nonlinear rupture of the energy bands, resulting in insulating behavior.engjournal article1079-7114https://doi.org/10.1103/PhysRevLett.112.087202https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.112.087202restricted access539.8621.38PhysicsBrownmilleriteStatesOxideFísica del estado sólidoElectrónica (Física)2211 Física del Estado Sólido2203 Electrónica