Facile synthesis of nanosized samarium titanate (Sm2Ti2O7) powders: structural, composition, thermal stability, optical and magnetic properties

Abstract

Samarium titanate nanopowders have been successfully synthesized from their corresponding precursors through a facile modified sol–gel route. The XRD pattern of the calcined sample at 1100 °C showed that the prepared materials are composed mainly of Sm₂Ti₂O₇ as a predominant phase. SEM images showed that the morphology of the materials changed from amorphous to crystalline agglomerated nanoparticles upon calcination of the as-precipitated sample at 400 to 1100 °C. The crystallite size of the calcined sample at 800 °C was in the range of 20–50 nm as calculated from the TEM images. UV-vis spectra revealed the presence of one absorption peak at around 307 nm for all samples and the band gap is about 3.13 eV on average. One emission peak around 360 nm (3.44 eV) was observed for all samples upon excitation at wavelengths of 240, 250, 265 and 320 nm of the dispersed powders in ethyl alcohol. XPS results showed that the oxygen vacancies increased as the calcination temperature increased, which might affect the physical properties of the calcined samples. The magnetic saturation decreased to 7.55 × 10⁻³ emu g⁻¹ upon calcination of the samples in air at 1100 °C. Based on the XRD, SEM, optical absorption and emission studies the prepared materials showed good crystal quality, implying that the Sm₂Ti₂O₇ nanostructures may suggest possible applications in optoelectronic devices and photochemical applications at low and high temperatures.