Artículo
Annealing effects on the magnetic and magnetotransport properties of iron oxide nanoparticles self-assemblies
Fabris, Fernando; Lima, Enio Junior
; Nuñez, Jorge Martín
; Troiani, Horacio Esteban
; Aguirre, Myriam H.; Leborán, Victor; Rivadulla, Francisco; Winkler, Elin Lilian
Fecha de publicación:
11/2023
Editorial:
IOP Publishing
Revista:
Nanotechnology
ISSN:
0957-4484
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
In magnetic tunnel junctions based on iron oxide nanoparticles the disorder and the oxidation state of the surface spin as well as the nanoparticles functionalization play a crucial role in the magnetotransport properties. In this work, we report a systematic study of the effects of vacuum annealing on the structural, magnetic and transport properties of self-assembled ∼10 nm Fe3O4 nanoparticles. The high temperature treatment (from 573 to 873 K) decomposes the organic coating into amorphous carbon, reducing the electrical resistivity of the assemblies by 4 orders of magnitude. At the same time, the 3.Fe2+/(Fe3++Fe2+) ratio is reduced from 1.11 to 0.13 when the annealing temperature of the sample increases from 573 to 873 K, indicating an important surface oxidation. Although the 2 nm physical gap remains unchanged with the thermal treatment, a monotonous decrease of tunnel barrier width was obtained from the electron transport measurements when the annealing temperature increases, indicating an increment in the number of defects and hot-spots in the gap between the nanoparticles. This is reflected in the reduction of the spin dependent tunneling, which reduces the interparticle magnetoresistance. This work shows new insights about influence of the nanoparticle interfacial composition, as well their the spatial arrangement, on the tunnel transport of self-assemblies, and evidence the importance of optimizing the nanostructure fabrication for increasing the tunneling current without degrading the spin polarized current.
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Articulos (UE-INN - NODO BARILOCHE)
Articulos de UNIDAD EJECUTORA INSTITUTO DE NANOCIENCIA Y NANOTECNOLOGIA - NODO BARILOCHE
Articulos de UNIDAD EJECUTORA INSTITUTO DE NANOCIENCIA Y NANOTECNOLOGIA - NODO BARILOCHE
Articulos(CCT - PATAGONIA NORTE)
Articulos de CTRO.CIENTIFICO TECNOL.CONICET - PATAGONIA NORTE
Articulos de CTRO.CIENTIFICO TECNOL.CONICET - PATAGONIA NORTE
Citación
Fabris, Fernando; Lima, Enio Junior; Nuñez, Jorge Martín; Troiani, Horacio Esteban; Aguirre, Myriam H.; et al.; Annealing effects on the magnetic and magnetotransport properties of iron oxide nanoparticles self-assemblies; IOP Publishing; Nanotechnology; 34; 45; 11-2023; 1-13
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