Photoacoustic spectroscopy of cobalt ferrite-based magnetic fluids

Abstract Photoacoustic (PA) spectroscopy was used in the investigation of citrate-coated, cobalt ferrite-based biocompatible magnetic fluid samples. Samples containing 4 and 16 nm core diameter ( D ) nanoparticles were investigated in the 0.3–1.0 μm wavelength region. The data obtained from the PA band-L indicated a higher citrate grafting coefficient in the 16 nm nanoparticle. Also, PA features in the band-C revealed a strong blue shift of the optical absorption band edge ( E BE ) associated to the 4 nm nanoparticle, due to the quantum confinement effect.