Abnormal Temperature Dependence of the Coercive Feld in FePt thin films

Authors
Guzmán, Jonás Manuel; Alvarez, Nadia Roxana; Salva, Horacio Ramon; Vasquez Mansilla, Marcelo; Gomez, Javier Enrique; Butera, Alejandro Ricardo
Publication Year
2013
Language
English
Format
article
Status
Published version
Description
We have observed notable changes in the magnetic response of FePt thin films that we have attributed to a transition in the magnetic domain structure when the film thickness or the temperature is varied. The critical thickness for this transition depends on the Q-factor, Q=Kperp/2PiMs^2, so that a change in thedomain structure is expected when changes in the perpendicular anisotropy, Kperp , or the saturation magnetization, Ms, occur. At room temperature these samples have Q ~ 0:3, and a transition between planar to stripe-like domains occurs for a film thickness d ~ 30 nm. Due to the different thermal expansion of the FePt alloy and the Si substrate a reduction in Q is predicted when the temperature is lowered. From magnetization vs. field loops measured at different temperatures below T=300 K, we have effectively observed a change in the coercive field which can be associated to a transition from stripe-like to in-plane domains. The transition temperature range is broad, indicating a gradual variation between the two magnetic configurations, but changes systematically with film thickness, consistent with an interfacial induced stress. A model that includes the temperature dependence of the strain and the magnetization, predicts correctly the observation of a larger critical thickness at lower temperatures.
Fil: Guzmán, Jonás Manuel. Universidad Nacional de Cordoba. Facultad de Ciencias Quimicas; Argentina
Fil: Alvarez, Nadia Roxana. Comisión Nacional de Energía Atómica. Gerencia del Area de Energía Nuclear. Instituto Balseiro; Argentina. Universidad Nacional de Cuyo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comision Nacional de Energia Atomica. Centro Atomico Bariloche; Argentina
Fil: Salva, Horacio Ramon. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Area de Energía Nuclear. Instituto Balseiro; Argentina. Universidad Nacional de Cuyo; Argentina. Comision Nacional de Energia Atomica. Centro Atomico Bariloche; Argentina
Fil: Vasquez Mansilla, Marcelo. Comisión Nacional de Energía Atómica. Gerencia del Area de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Cuyo; Argentina
Fil: Gomez, Javier Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comision Nacional de Energia Atomica. Centro Atomico Bariloche; Argentina. Universidad Nacional de Cuyo; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Area de Energía Nuclear. Instituto Balseiro; Argentina
Fil: Butera, Alejandro Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte; Argentina. Comision Nacional de Energia Atomica. Centro Atomico Bariloche; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Area de Energía Nuclear. Instituto Balseiro; Argentina. Universidad Nacional de Cuyo; Argentina
Subject
FePt
THIN FILMS
MAGNETIC ANISOTROPY
CRITICAL THICKNESS
STRAIN INDUCED ANISOTROPY
Física de los Materiales Condensados
Ciencias Físicas
CIENCIAS NATURALES Y EXACTAS
Access level
Restricted access
License
https://creativecommons.org/licenses/by-nc-nd/2.5/ar/
Repository
CONICET Digital (CONICET)
Institution
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identifier
oai:ri.conicet.gov.ar:11336/11059