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Magnetization of Fe3O4 and Co-doped Fe3O4 islands by XMCD-PEEM - Juan DE LA FIGUERA

Instituto de Quimica Fisica "Rocasolano", Madrid, Espagne

Bât T-18 – Parc Club Orsay – Salle de réunion

Magnetite and cobalt ferrite are ferrimagnetic, where changing their cobalt/iron ratio can be used to tune their electronic and magnetic properties within the same spinel structure. One concern for their possible use in spintronic applications is that their magnetic properties as thin films are strongly affected by growth defects such as antiphase domain boundaries. Iron [1] and cobalt-iron spinels [2] can be grown up as micrometer-wide flat islands on metal substrates by using the proper growth conditions in reactive molecular beam epitaxy. As the islands arise each from a single nuclei, they should be free of antiphase boundaries. We follow their growth by low-energy electron microscopy and study the magnetic domain patterns by means of x-ray magnetic circular dichroism in photoemission microscopy. Rotating the sample allows to determine the 3D magnetization vector and compare it with micromagnetic simulations in islands from nanometer thickness up to a hundred nanometers. We have observed in remanence magnetic domains which are orders of magnitude larger that those typically observed in thin films.

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L. Martín-García, A. Quesada, C. Munuera, J.F. Fernández, M. García-Hernández, M. Foerster, L. Aballe, J. de la Figuera. "Atomically flat ultrathin cobalt ferrite islands". Adv. Mat., 27 (2015) 5955, DOI : 10.1002/adma.201502799


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