Author(s): Soga, Diogo ; Alves, Sarah ; Campos, Alex Fabiano Cortez ; Tourinho, Francisco Augusto ; Depeyrot, Jérôme ; Figueiredo Neto, Antonio Martins
Date: 2010
Origin: Oasisbr
Subject(s): Partículas magnéticas; Nanopartículas magnéticas; Partículas magnéticas; Partículas magnéticas; Nanopartículas magnéticas; Nanopartículas magnéticas
7 f. : il.
The Z-scan technique is used to measure the nonlinear refractive index n2 and the nonlinear absorption coefficient β of ionic magnetic colloids as a function of the nanoparticles’ diameter (Drx) in the femto- and millisecond time-scale regimes. A change from a convergent-lens type (at a femtosecond time scale) to a divergent-lens type behavior (at a millisecond time scale) is observed. From the values of n2 and β measured in the femtosecond time-scale regime, the third-order susceptibility X(³) is calculated and is shown to depend on Drx: the smaller the Drx, the bigger the X(³). A possible origin of the high values of X(³) found may be confining effects related to the physical nanoscale of the magnetic particles.
