Structural investigation in strontium titanate (SrTiO3) synthesized by gel-combustion method and in-gelation method: a TDPAC and XRD study

Abstract

The present work reports the results of structural investigations on strontium titanate (STO), synthesized by two different methods, by time-differential perturbed angular correlation (TDPAC) technique and X-ray diffraction (XRD) technique. STO was synthesized by two different methods: gel-combustion and in-gelation (also known as internal gelation) method and the samples were doped with 181Hf as TDPAC probe to study local structure at cationic sites of Titanium. The XRD analysis of sample synthesized by gel-combustion method (hereafter referred to as STO-GC) was found to be pure STO phase whereas that synthesized by in-gelation method (hereafter referred to as STO-IG) was found to have titania (19.9% w/w) as impurity phase. TDPAC spectroscopy was found to be very sensitive method for revealing the presence of miniscule amount of rutile phase of TiO2 in STO-GC, which was difficult to detect by conventional XRD. TDPAC study on STO-IG showed the presence of only rutile TiO2 phase, which indicated preferential doping of TDPAC probe (181Hf) at Ti-site of rutile TiO2 than Ti-site of STO. Probable route of formation of rutile phase in STO obtained from in-gelation method has been discussed.