Photo-induced electric polarizability of Fe3O4 nanoparticles in weak optical fields

Using a developed co-precipitation method, we synthesized spherical Fe 3 O 4 nanoparticles with a wide nonlinear absorption band of visible radiation. Optical properties of the synthesized nanoparticles dispersed in an optically transparent copolymer of methyl methacrylate with styrene were studied by optical spectroscopy and z-scan techniques. We found that the electric polarizability of Fe 3 O 4 nanoparticles is altered by low-intensity visible radiation ( I ≤ 0.2 kW/cm 2 ; λ = 442 and 561 nm) and reaches a value of 10 7 Å 3 . The change in polarizability is induced by the intraband phototransition of charge carriers. This optical effect may be employed to improve the drug uptake properties of Fe 3 O 4 nanoparticles. PACS 33.15.Kr, 78.67.Bf, 42.70.Nq