Influence of Fe3O4 nanoparticles on structural, optical and magnetic properties of erbium doped zinc phosphate glass

Tunable modifications of physical and optical properties of metallic nanoparticles (NPs) embedded rare earth (RE) doped inorganic binary glasses are the key issue. Series of glass with composition (69-x)P2O5-30ZnO-1Er2O3-(x)Fe3O4, where 0 = x = 2 mol% containing Fe3O4 NPs are prepared by melt quenching method and characterized using XRD, UV-Vis-NIR, PL, TEM and vibrating sample magnetometer (VSM) techniques. The Fe3O4 NPs concentration dependent density, molar volume, structural, magnetic and optical properties are determined. The XRD pattern confirms the amorphous nature of all samples. The glass density is found increase and molar volume decrease with the increase of NPs concentration. The TEM micrographs reveal the presence of spherical NPs of average diameter ~26 nm with homogenous distribution. The UV-Vis-NIR absorption spectra exhibit ten absorption bands centered at 376, 406, 448, 486, 522, 546, 652, 798, 976 and 1534 nm corresponding to the absorption from 4I15/2 ground state to various excited states of Er3+ ions. The optical band gap energy for direct (4.47-3.64 eV) and indirect (4.27-3.53 eV) transitions and Urbach energy (0.65-0.15 eV) are found to decrease with the increase of Fe3O4 contents. The decrease in band gap energy is ascribed to the creation of non bridging oxygen (NBO) ions in the glass network. The emission spectra at 478 nm excitations display two prominent peaks centered at 532 and 634 nm originate from 4S3/2 → 4I15/2 and 4F9/2 → 4I15/2 transitions, respectively. Furthermore, increasing NPs concentration dependent luminescence quenching is attributed to the energy transfer from the erbium ion to NPs. These glasses displaying ferrimagnetic behavior in the concentration range of 1.5-2 mol% of NPs verify the presence of iron oxide or ferrite in the glass sample are useful for magneto-optic devices