Mercoledì 24 Febbraio 2016, alle ore 11.30,
presso l'Aula Riunioni della Sezione di Fisica,
in Via Roma 56, Siena,
Liliana Losurdo
presenterà un seminario di Dottorato in Fisica Sperimentale dal titolo
"Time-dependence in Néel relaxation theory."
Abstract: The Néel relaxation theory was introduced to explain time-dependent magnetic phenomena.
By starting from the magnetic properties of the materials and their spontaneous magnetization, it is possible to define a superparamagnetic state of a nanoparticle system: when a change in the applied field or temperature occurs, this system will approach an equilibrium value of magnetization with a characteristic relaxation time tN.
In order to describe the time-dependent decay of an isothermal remanent magnetization of a superparamagnetic particle system, a new model is introduced: it is based on the summation of relaxation times over a very narrow range of the particle size distribution.
Then, analytical expressions can be obtained for small and large t.
Finally, some applications in the magnetic relaxometry are shown as very sensitive methods in detecting cells and other targeted diseases.