Optical and EPR Properties of Mn- and Eu-Activated LaMgAl11O19 Phosphor

LaMgAl11O19 phosphor doped with Eu and Mn ions has been prepared by the urea combustion route. The as-prepared phosphor was studied using X-ray diffraction, electron paramagnetic resonance (EPR), diffuse reflectance and photoluminescence studies. The EPR spectra of LaMgAl11O19:Eu, Mn phosphor exhibit signals with the effective g values at g = 1.98, 4.29 and 7.23. The resonance signals at g = 1.98 and 4.29 were attributed to Mn2+ ions in tetrahedral and rhombic environment, respectively. The resonance signal at g = 7.23 was attributed to Eu2+ ions. The optical spectrum of this phosphor exhibits an intense band in the visible region and this band has been attributed to spin-allowed 5Eg → 5T2g transition of Mn3+ ions. Upon excitation at 324 nm, the material displays emission in the blue, green and red spectral region.