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oai:docta.ucm.es:20.500.14352/130142023-08-26T00:15:16Zcom_20.500.14352_14col_20.500.14352_15

00925njm 22002777a 4500 dc Ruiz Gómez, Sandra author Pérez García, Lucas author Mandziak, Anna author Figuera, Juan de la author Delgado Soria, Guiomar author Prieto Recio, Pilar author Quesada, Adrián author Foerster, Michael author Aballe, Lucía author 2018-12-19 We demonstrate the preparation of ultrathin Fe-rich nickel ferrite (NFO) islands on a metal substrate. Their nucleation and growth are followed in situ by low-energy electron microscopy (LEEM). A comprehensive characterization is performed combining LEEM for structural characterization and PEEM (PhotoEmission Electron Microscopy) with synchrotron radiation for chemical and magnetic analysis via X-ray Absorption Spectroscopy and X-ray Magnetic Circular Dichroism (XAS-PEEM and XMCD-PEEM, respectively). The growth by oxygen-assisted molecular beam epitaxy takes place in two stages. First, islands with the rocksalt structure nucleate and grow until they completely cover the substrate surface. Later three-dimensional islands of spinel phase grow on top of the wetting layer. Only the spinel islands show ferromagnetic contrast, with the same domains being observed in the Fe and Ni XMCD images. The estimated magnetic moments of Fe and Ni close to the islands surface indicate a possible role of the bi-phase reconstruction. A significant out-of-plane magnetization component was detected by means of XMCD-PEEM vector maps. 2045-2322 10.1038/s41598-018-36356-6 https://hdl.handle.net/20.500.14352/13014 http://dx.doi.org/10.1038/s41598-018-36356-6 https://www.nature.com Structure and magnetism of ultrathin nickel-iron oxides grown on Ru(0001) by high-temperature oxygen-assisted molecular beam epitaxy