Magnetic and photoluminescence properties of rare-earth substituted quaternary spinel ferrite nanoparticles

Abstract

Rare earth substituted quaternary spinel ferrites Ni0.5Zn0.5Fe1.95Eu0.05O4, Co0.5Zn0.5Fe1.95Dy0.05O4, and Cu0.5Zn0.5Fe1.95Tb0.05O4 were prepared by a low-temperature co-precipitation method without any post heat treatment. Structural confirmation of the prepared materials was done by XRD. Using TEM, their morphology was investigated. Magnetic studies were conducted using VSM. The prepared materials exhibit soft ferrimagnetic nature. The magnetization curves were further studied by applying the law of approach to saturation. Downconversion and upconversion photoluminescence properties of the prepared materials were investigated at different excitation wavelengths. No characteristic emission spectra of the rare-earths elements were observed. In the case of downconversion, a broad emission band formed by sub-bands and in the upconversion spectra, characteristic emission peaks were observed in all compositions. The observed emission spectra depict the presence of multiple energy levels within the band gap of spinel ferrites.