Influence of Mn Doping on the Crystal Structure, and Optical and Magnetic Properties of Compounds

This paper presents the influence of Mn doping on the structural characterization, and optical and magnetic properties of SrTi_1-xMn_xO₃(x = 0.0-0.1) materials prepared by a solid-state reaction method. The detailed analyses of X-ray diffraction patterns indicate an incorporation of Mn dopants into Ti sites of the SrTiO₃ host lattice. There is a cubic to tetragonal transformation, which takes place at a threshold concentration x ≈ 0.04. The optical absorption spectra show a rapid increase in the absorption coefficient. The bandgap energy (Eg) related to the direct electron transition decreases with increasing Mn concentration: Eg decreases from 3.15 eV for x = 0 to 1.28 eV for x = 0.10. From this point of view, the SrTi_1-xMn_xO₃ materials are considered as promising materials for photocatalytic applications. Interestingly, while the samples with x = 0.0-0.02 are diamagnetic, the others with x = 0.04-0.10 exhibit weak ferromagnetism. The ferromagnetic order increases with increasing Mn concentration. Based on the results of structural and optical analyses, the nature of magnetism in the samples is explained thoroughly.