Magnetic properties and heat capacity of CoTiO₃nanopowders prepared by stearic acid gel method

Pure cobalt titanate nanopowders were successfully prepared in wet-chemistry synthesis method, using cobalt acetate and tetra-n-butyl titanate as Co and Ti sources and stearic acid as complexing reagent. The gel was calcined at different temperatures in air ranging from 500°C to 650°C. Results of thermal analysis are given; including both differential thermal gravimetry (DTG) and thermogravimetric. X-ray diffraction was used to characterise the crystallisation process, the particle size and morphology of the calcined powders. The results indicated that cobalt nanopowders with a particle size of about 35 nm could be obtained after calcinations of the dried gel at 600°C for 2 h. In the temperature range between 80°C and 500°C, the empirical equation (C P (JK−1 mol−1) = −136.311 + 0.141 T − 3.551 × 107/T 2) for the C P of CoTiO3 was determined from differential scanning calorimetry. The synthesised CoTiO3 indicate a superparamagnetic behaviour, as evidenced by using vibrating sample magnetometer at room temperature.