Magneto-Optic Studies On Rare Earth Containing Glasses And On Ii-Vi Semiconductor Quantum Dots In Glasses: Nonlinear Effects

Faraday rotation has been measured at room temperature and at magnetic field strengths up to 2.57T for II-VI type semiconductor nanocrystals (CdS, CdSe, and CdTe) in the form of quantum dots embedded in borosilicate glass matrix and for rare earth containing glasses. The graph of Faraday rotation versus field strength for all quantum dots showed "kinks" (abrupt slope changes) which is evidence for a nonlinear Faraday effect. The field strength at which these kinks occur for the nanoparticles varies inversely with quantum dot sizes. Given the inverse linearity seen in dot size versus magnetic field, possible causes such as exciton coulomb interactions were considered as a mechanism for the enhanced Faraday rotation. The rare earth containing glasses also showed non-linearity in the Faraday rotation as function of magnetic field strength.