Magnetic Quenching of Plasmon-photonic Activities in Fe$_{3}$O$_{4}$-Elastomer Composite*

We present preliminary results on the effect of particle size on the optical response of Fe$_{3}$O$_{4}$-silicone elastomer composite in the presence of external static magnetic field. The optical response of composites containing 2wt{\%} of Fe$_{3}$O$_{4}$ particles of diameter range 20-30nm, 40-60 nm and d$<$500nm in silicone elastomer were measured using a PerkinElmer lambda 950 UV/vis/NIR spectrometer. We observed a systematic redshift in the optical response of composites containing nanoparticles (20nm-30nm and 40-60nm) with increasing static magnetic field strength, which saturates near 600 Gauss. However, we observed a dramatic suppression to near quenching of the plasmonic activities in the micron size particle (d $<$ 500nm) elastomer composites. This occurred even at very low applied static magnetic fields, suggesting particle size limitations in modulation of plasmon-photonics by external magnetic field.