Tuneable magnetic patterning of paramagnetic Fe60Al40 (at. %) by consecutive ion irradiation through pre-lithographed shadow masks
Varea Espelt, Aïda (Universitat Autònoma de Barcelona. Departament de Física)
Suriñach, Santiago (Suriñach Cornet) (Universitat Autònoma de Barcelona. Departament de Física)
Menéndez Dalmau, Enric (Universitat Autònoma de Barcelona. Departament de Física)
Montserrat, J. (Centro Nacional de Microelectrónica)
Lora-Tamayo d'Ocón, Emilio (Centro Nacional de Microelectrónica)
Weber, A. (Paul Scherrer Institut (Suïssa))
Heyderman, L. J. (Paul Scherrer Institut (Suïssa))
Deevi, S. C. (Philip Morris. Research Center)
Rao, K. V. (Kungl. Tekniska högskolann. Materialfysik)
Baró, M. D.. (Universitat Autònoma de Barcelona. Departament de Física)
Buchanan, K. S. (Colorado State University. Department of Physics)
Nogués, Josep (Institut Català de Nanociència i Nanotecnologia)
Sort Viñas, Jordi (Universitat Autònoma de Barcelona. Departament de Física)

Fecha:	2011
Resumen:	Arrays of ferromagnetic circular dots (with diameters ranging from 225 to 420 nm) have been prepared at the surface of atomically ordered paramagnetic Fe60Al40 (at. %) sheets by means of ion irradiation through prelithographed poly(methyl methacrylate) (PMMA) masks. The cumulative effects of consecutive ion irradiation (using Ar+ ions at 1. 2 × 1014 ions/cm2 with 10, 13, 16, 19 and 22 keV incident energies) on the properties of the patterned dots have been investigated. A progressive increase in the overall magneto-optical Kerr signal is observed for increasingly larger irradiation energies, an effect which is ascribed to accumulation of atomic disorder. Conversely, the coercivity, HC, shows a maximum after irradiating at 16-19 keV and it decreases for larger irradiation energies. Such a decrease in HC is ascribed to the formation of vortex states during magnetization reversal, in agreement with results obtained from micromagnetic simulations. At the same time, the PMMA layer, with an initial thickness of 90 nm, becomes progressively thinned during the successive irradiation processes. After irradiation at 22 keV, the remaining PMMA layer is too thin to stop the incoming ions and, consequently, ferromagnetism starts to be generated underneath the nominally masked areas. These experimental results are in agreement with calculations using the Monte-Carlo simulation Stopping Range of Ions in Matter software, which show that for exceedingly thin PMMA layers Ar+ ions can reach the Fe60Al40 layer despite the presence of the mask.
Ayudas:	Ministerio de Ciencia e Innovación MAT2010-20616-C02-02 Ministerio de Ciencia e Innovación MAT2007-61629 Agència de Gestió d'Ajuts Universitaris i de Recerca 2009/SGR-1292
Nota:	This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.
Derechos:	Tots els drets reservats.
Lengua:	Anglès
Documento:	Article ; recerca ; Versió publicada
Materia:	Materials ; Propietats magnètiques
Publicado en:	Journal of applied physics, Vol. 109, Núm. 9 (May 2011) , p. 093918/1-093918/7, ISSN 1089-7550

DOI: 10.1063/1.3590158

7 p, 2.5 MB

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