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| Author(s): |
Gabriel Teixeira Landi
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Instituto de Física (IF/SBI) |
| Defense date: | 2012-03-08 |
| Examining board members: |
Antonio Domingues dos Santos;
Roberto Bechara Muniz;
Mario Jose de Oliveira;
Nilson Antunes de Oliveira;
Luis Gregorio Godoy de Vasconcellos Dias da Silva
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| Advisor: | Antonio Domingues dos Santos |
| Abstract | |
This thesis concerns the use of computer models to study the magnetic properties of nanoparticles at a finite temperature. These materials, which are of great academic and applied interest, are known to have an enhanced sensitivity to thermal fluctuations -- a phenomenon known as superparamagnetism. Such a peculiar nature is responsible for a large number of interesting physical phenomena, which are known to extend over a wide range of experimental situations. These include, among others, geomagnetism, ultra-fast devices and oncological treatments. The model employed, known as the Néel-Brown theory, introduces in the dynamical equation an stochastic term representing the thermal fluctuations. It\'s range of validity is quite broad, thus being applicable to all of the aforementioned situations. We implemented a highly efficient numerical library, whose scope extends over a large range of experiments. In this thesis we focused on the problem of dynamic hysteresis, which has receive considerable attention in recent years. This was motivated, among other things, by the potential use of nanoparticles in magneto-hyperthermia treatments. (AU) | |
| FAPESP's process: | 09/00503-7 - Study of composites of hard and soft magnetic materials produced using the gas aggregation methodology |
| Grantee: | Gabriel Teixeira Landi |
| Support Opportunities: | Scholarships in Brazil - Doctorate |