Tesis doctoral de Enric Menéndez Dalmau
In recent years, intense research is being pursued in the development of novel methods for the fabrication of arrays of ordered magnetic nanostructures. Fe60ai40 (at. %) Alloys and austenitic stainless steels show an interesting combination of magnetic and structural properties, which make them turn into potential candidates to be magnetically patterned. Namely, from the magnetic point of view, whereas atomically ordered fe60ai40 (at. %) Is paramagnetic at room temperature, disordered fe60ai40 becomes ferromagnetic. Concerning austenitic stainless steels, due to mechanical deformation, a phase transformation from the paramagnetic austenite phase to the ferromagnetic martensite phase can occur in these ferrous alloys. In addition, nitriding of austenitic stainless steels at moderate temperatures is able to partially transform the austenite phase into the supersaturated nitrogen solid solution, often called in the literature «expanded austenite» phase, which shows ferromagnetic behavior. This thesis is mainly focused on the generation of ordered arrays of micro/nanoscaled ferromagnetic entities (i.E., Magnetic patterning), embedded in a paramagnetic matrix, at the surface of either fe60ai40 (at. %) Alloys or austenitic stainless steels. This is accomplished by taking advantage of the magnetic transitions which occur in these alloys upon local plastic deformation (nanoindentation) and controlled ion irradiation (focused ion beam and broad beam noble gas ion irradiation through shadow masks in feal alloys and ion beam nitriding through shadow masks in austenitic stainless steels). Furthermore, a detailed study of the structural, mechanical and magnetic changes which take place in these materials upon either mechanical deformation or ion irradiation is presented.
Datos académicos de la tesis doctoral «Generation of ferromagnetism on non-magnetic materials«
- Título de la tesis: Generation of ferromagnetism on non-magnetic materials
- Autor: Enric Menéndez Dalmau
- Universidad: Autónoma de barcelona
- Fecha de lectura de la tesis: 26/11/2008
Dirección y tribunal
- Director de la tesis
- Josep Nogues Sanmiquel
- Tribunal
- Presidente del tribunal: María dolores Baró mariné
- amadeu Concustell fargas (vocal)
- jí¼rgen Fassbender (vocal)
- Fernando Plazaola muguruza (vocal)