The impact of cobalt oxide additions and heat treatment on wollastonite for magnetic applications.

Magnetic nanocomposite was prepared using the wet chemical precipitation approach with varying amounts of cobaltous oxide (CoO). The concentrations of CoO were 0.5, 3.5, 6.5, and 9.5 g per 100 % wollastonite composition. Samples were sintered separately at 1000 and 1200 °C. X-ray diffraction analysis (XRD) of the sintered parent sample revealed the formation of wollastonite CaSiO 3 and larnite Ca 2 SiO 4 , as well as a minor silicon oxide SiO 2 phase. In CoO-doped samples, Co-åkermanite Ca 2 CoSi 2 O 7 and other phases were formed. The XRD and scanning electron microscope SEM confirm the samples' submicron and nanocrystalline microstructure. The Fourier transform infrared spectroscopy (FTIR) and Raman spectra (RS) of investigated samples sintered at 1000 and 1200 °C revealed their bond structure. Both analyses confirmed that incorporating CoO into CaSiO 3 significantly improved its vibrational modes, reflecting structural modifications. By increasing the cobalt oxide content from 3.5 to 9.5 wt%, the samples attain the ideal paramagnetic state, as demonstrated by the magnetic hysteresis (M − H) curve, which is linearly reversible. Formation of the Ca 2 CoSi 2 O 7 significantly alters the magnetic characteristics of the samples, whether through increasing the cobalt oxide concentration up to 9.5 wt% or modifying the sintering temperature. This enables the prepared nonocomposites to be suitable for novel magnetic applications. [ABSTRACT FROM AUTHOR]