Tuning of structural and optical properties by sintering of multiferroic GdMnO₃ precursor

Abstract

Multiferroic GdMnO3 was synthesized by the modified sol-gel route. The GdMnO3 precursor were sintered for 2 hours at different temperatures ranging from 300 (GMO300) to 800°C (GMO800). X-ray diffraction pattern shows that the crystallinity improves with sintering temperatures. The Raman data and Fourier transform infrared analysis also support the X-ray diffraction data. UV-Visible spectrum of the sample GMO300 shows absorption peak at 2.39 eV whereas the completely crystallized sample sintered at 800°C (GMO800) shows two absorption bands at 2.25 and 2.56 eV. These bands are attributed to the Mn (d-d) transitions. Higher energy bands at (3.27 and 4.94 eV) of GMO700 and (3.26, 4.40, 4.74 and 5.08 eV) of GMO800 are attributed to the charge transfer transitions from O(2p) to Mn(3d) state. Moreover, the completely crystallized sample (GMO800) exhibits the signature of magneto-dielectric coupling.