In situ modification of the magnetocrystalline anisotropy in cobalt-ferrite microcrystals

We present the in situ modification of the magnetocrystalline anisotropy of iron-rich cobalt-ferrite epitaxial islands by changing their composition. Crystalline cobalt-ferrite spinel islands have been grown by oxygen-assisted molecular beam epitaxy on a Ru(0001) single crystal. The micro-crystals a...

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Detalles Bibliográficos
Autores: Mandziak, Anna, Prieto, J. E., Dávalos, J.Z., Prieto, Pilar, Foerster, Michael, Aballe, Lucía, de la Figuera, Juan
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2025
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/377863
Acceso en línea:http://hdl.handle.net/10261/377863
Access Level:acceso abierto
Palabra clave:Cobalt ferrites
In-situmodification
Photoemission microscopy
Descripción
Sumario:We present the in situ modification of the magnetocrystalline anisotropy of iron-rich cobalt-ferrite epitaxial islands by changing their composition. Crystalline cobalt-ferrite spinel islands have been grown by oxygen-assisted molecular beam epitaxy on a Ru(0001) single crystal. The micro-crystals are several micrometers wide with heights of tens of nanometers. Their spatially-resolved vector magnetization is mapped by x-ray magnetic circular dichroism in photoemission microscopy at the L absorption edges of Co and Fe. Thick islands present a closure-like magnetic domain structure with the magnetization directions predominantly aligned along the projections of the easy magnetic axes onto the (111) surface plane. Thinner islands are more affected by growth defects and present a more complex domain structure. Upon deposition of additional Fe in an oxygen background pressure, Co is found to segregate out of the spinel islands, while their Fe content increases. This produces a reduction in the magnetocrystalline anisotropy, which manifests as a reorientation of the magnetization directions towards the edges of the islands, reflecting an increased contribution of the shape anisotropy.