Abnormal Temperature Dependence of the Coercive Feld in FePt thin films
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 c...
| Autores: | , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2013 |
| País: | Argentina |
| Institución: | Consejo Nacional de Investigaciones Científicas y Técnicas |
| Repositorio: | CONICET Digital (CONICET) |
| Idioma: | inglés |
| OAI Identifier: | oai:ri.conicet.gov.ar:11336/11059 |
| Acceso en línea: | http://hdl.handle.net/11336/11059 |
| Access Level: | acceso abierto |
| Palabra clave: | Fept Thin Films Magnetic Anisotropy Critical Thickness Strain Induced Anisotropy https://purl.org/becyt/ford/1.3 https://purl.org/becyt/ford/1 |
| Sumario: | 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. |
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