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

In this paper, the influences of the Mn²⁺ doping on the structure, optical, and magnetic properties of PbTi_1-x Mn_xO₃ (with x = 0.00, 0.03, 0.06, 0.08, 0.10, and 0.12), prepared by the sol-gel method have been investigated by X-ray diffraction (XRD), Raman scattering, optical absorption, and vibrating sample magnetometer measurements. The detailed analysis of XRD patterns showed that the tetragonal lattice distorted ratio (c/a) decreased undesirably with the increasing of Mn content. However, c/a ratio increased again after calcining at higher temperature. The shift to the lower wavenumber and the broadening of some Raman peaks, such as E(2TO) and A1(2TO), indirectly indicated the incorporation of Mn²⁺ ions into PbTiO₃ (PTO) lattice. Absorption spectra exhibited a remarkable decrease of effective optical bandgap (E_g) from 2.99 eV for pure PTO to 1.5 eV for Mn-doped PTO. Therefore, Mn-doped PTO material may be considered as a promising material for photovoltaic and photocatalytic application. In addition, the diamagnetic nature of pure PTO disappeared and the ferromagnetism gradually increased as the Mn content increases. The saturation magnetization M_s varied from 0.014 emu/g for pure PTO to 0.064 emu/g for the PbTi_0.88 Mn_0.12O₃ (Mn12) sample. The nature of this ferromagnetic order in samples could be assigned to the incorporation of ion Mn²⁺ in PTO lattice.