Abstract
The magnetic properties and local order of cobalt/silicon nitride metal-insulator multilayered system have been studied. Magnetization characterization reveals an evolution of the magnetic features by varying the metal layer thickness. Results show that multilayers with larger metal thickness (t) present a pure ferromagnetic character, whereas samples with t < 2 nm exhibit a granular superparamagnetic behavior, as it corresponds to discontinuous metal-insulator materials. An important decrease in the magnetization values for the clustered samples has also been observed. X-ray absorption near edge spectroscopy (XANES) and extended x-ray absorption fine structure (EXAFS) at the Co K-edge have been used to determine the local order and electronic configuration around cobalt. Results reveal the formation of an intermediate CoN phase likely located at the Co/Si3N4 interface. Further insight in the electronic structure of cobalt atoms has been investigated through ab-initio XANES calculations based on Green function’s multiple scattering formalism. Local-projected density of states (l-DOS) obtained by simultaneous computations has unveiled the effects of the nitrogen coordination in the electronic structure of the metal atom around the Fermi energy.
Keywords
magnetic properties, x-ray absorption near edge spectroscopy, XANES
Subject Categories
Electric insulators and insulation, Cobalt - Magnetic properties, Silicon nitride - Magnetic properties
Disciplines
Chemical Engineering
Publisher
American Institute of Physics
Publication Date
12-5-2011
Rights Information
Copyright 2011
Rights Holder
American Institute of Physics
Recommended Citation
Jiménez-Villacorta, Félix; Espinosa, A.; Cespedes, E.; and Prieto, C., "Magnetic properties and short-range structure analysis of granular cobalt silicon nitride multilayers" (2011). Chemical Engineering Faculty Publications. Paper 12.
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Additional Files
magneticfig1.tif (266 kB)magneticfig2.tif (398 kB)
magneticfig3.tif (240 kB)
magneticfig4.tif (446 kB)
magneticfig5.tif (598 kB)
magneticfig6.tif (121 kB)
magneticfig7.tif (711 kB)
Notes
Originally published in Journal of Applied Physics v.110 (2011): 113909. DOI: 10.1063/1.3665877.