Characteristic spectroscopic properties of γ-irradiated rare-earth oxide-based ferrofluids

Abstract

Ferrofluids are being considered as potential candidates both in basic and applied research owing to their novel optical and magneto-optical properties. We have synthesised surfactant (N-Cetyl-N,N,N-trimethylammonium bromide, CTAB)-coated nanoscale gadolinium oxide (Gd 2O 3) based ferrofluids and then irradiated by gamma (γ-) rays with doses in the range of 32 Gy-2.635 kGy. High-resolution transmission electron microscope (HRTEM) analysis shows that the particles have developed intragranular defects owing to γ-ray irradiation. Fourier transform infrared (FT-IR) and photoluminescence (PL) studies also support the formation of defect ordering upon irradiation. Further, PL study indicates abrupt change of the symmetry factor with increase in γ-dose. By viewing the nature of variation between relative intensity of the defect-related emission and dose-dependent symmetry factor, one can predict the tunability of PL response. A proper understanding of the PL response of the irradiated nanoscale rare-earth oxides would find new avenues for lasing and other optoelectronic/photonic devices. © 2012 Copyright Taylor and Francis Group, LLC.