Jordán Ringgold, Daniel (2018) Estudio de la rugosidad en paredes de dominio en GdFeCo. / Study of the roughness of domain walss in GdFeCo. Maestría en Ciencias Físicas, Universidad Nacional de Cuyo, Instituto Balseiro.
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Resumen en español
En los materiales ferromagnéticos se suelen observar, en el rango de pequeños campos magnéticos, la coexistencia de dominios cuyas magnetizaciones apuntan en sentidos diferentes. En particular, en las películas delgadas con anisotropía magnética perpendicular, la dirección de la magnetización de los dominios apunta siempre perpendicular al plano de la muestra, prefiriendo dos posibles direcciones. La región donde ocurre la transición de un dominio a otro se denomina pared de dominio magnético. La energía elástica en la pared, la temperatura, los campos magnéticos externos y el desorden propio de la muestra compiten entre sí causando que las paredes de dominio sean rugosas. Esta rugosidad, una propiedad geométrica de la pared de dominio, codifica información sobre las interacciones presentes en el material. Utilizando microscopía magneto-óptica por efecto Kerr polar y análisis de imágenes, desarrollamos un método para cuantificar la rugosidad de paredes de dominio magnéticas como una medida de las fluctuaciones en la posición de la pared de dominio. De este análisis se obtienen dos parámetros relevantes: el exponente de rugosidad, que caracteriza el crecimiento de la rugosidad como una ley de potencia con respecto a la longitud de escala, y la amplitud, que es una medida directa de la magnitud de estas fluctuaciones. En esta tesis, utilizando el método desarrollado, presentamos un estudio estadístico del exponente de rugosidad y la amplitud en películas delgadas ferrimagnéticas de GdFeCo. En particular discutimos cómo cambian estos parámetros cuando se aplica un campo magnético en el plano de la muestra. Presentamos también una herramienta computacional diseñada específicamente para este trabajo.
Resumen en inglés
It is commonly observed in ferromagnetic materials, in the range low magnetic elds, the coexistence of domains whose magnetizations point in different directions. In particular, in thin magnetic lms with perpendicular magnetic anisotropy, the direction of the domain magnetization always points perpendicular to the plane of the sample, prefering two possible directions. The region where the transition occurs from one domain to the other is called the magnetic domain wall. The elastic energy of the wall, the temperature, the external magnetic fields, and the sample's intrinsic disorder compete amongst them causing the wall to be rough. This roughness, a geometrical property of the domain wall, codies information about the interactions present in the material. Using polar magneto-optic Kerr effect microscopy and image analysis, we developed a method to quantify the roughness of the magnetic domain wall, as a measure of the fluctuations in the position of the wall. From this analysis two relevant parameters are obtained: the roughness exponent, which describes the growth of the roughness as a power law with respect to the scale length, and the amplitude, which is a direct measure of the magnitude of these fluctuations. In this thesis, using the method we developed, we present a statistical study of the roughness exponent and amplitude in ferrimagnetic GdFeCo thin lms. Particularly, we discuss how these parameters change when an in-plane magnetic eld is applied. We also present a computational tool designed specically for this work.
| Tipo de objeto: | Tesis (Maestría en Ciencias Físicas) |
|---|---|
| Palabras Clave: | Magnetic fields; Campos magnéticos; [Magnetic thin films; Películas magnéticas delgadas; Magnetic domain walls; Paredes de dominios magnéticos; Dynamics of interfaces; Dinámica de interfases] |
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| Materias: | Física > Materia condensada |
| Divisiones: | Gcia. de área de Investigación y aplicaciones no nucleares > Gcia. de Física > Materia condensada > Teoría de sólidos |
| Código ID: | 752 |
| Depositado Por: | Tamara Cárcamo |
| Depositado En: | 14 Nov 2019 13:32 |
| Última Modificación: | 14 Nov 2019 13:32 |
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