M B KHANVILKAR
Articles written in Bulletin of Materials Science
Volume 40 Issue 7 December 2017 pp 1335-1345
R A PAWAR A K NIKUMBH D S BHANGE N J KARALE D V NIGHOT2 M B KHANVILKAR
The rare-earth ruthenium pyrochlores Ln$_2$Ru$_2$O$_7$ (Ln $=$ La$^{3+}$, Pr$^{3+}$, Nd$^{3+}$, Sm$^{3+}$ and Gd$^{3+}$) have been synthesized by the tartrate co-precipitation method, which allowed control of their composition and morphology. The preparation processes were monitored by thermal studies (TG-DTA). The obtained ruthenates were characterized by X-ray diffraction (XRD), TEM, d.c. electrical conductivity, thermoelectric power and dielectric constant measurements. X-ray diffraction patterns for all pyrochlore samples indicate a single-phase crystalline material with a cubic structure except for LaRuO$_3$, which shows perovskite orthorhombic structure. The structural parameter for the solid obtained was successfully determined by Rietveld refinement based on the analysis of powder XRD pattern. The TEM photographs of these compounds exhibited the average particle size in the range of 36.4–73.8 nm. The data on the temperature variation of d.c. electrical conductivity showed that all rare-earth ruthanates are semiconductors and major carriers are electrons. The conduction mechanism of these compounds seems to be oxygen non-stoichiometry. The variation of dielectric constant at various frequencies showed initially interfacial polarization up to 275 kHz and beyond, which shows domain wall motion.
Volume 45 All articles Published: 24 May 2022 Article ID 0092
A V NAGAWADE A K NIKUMBH N J KARALE M B KHANVILKAR A S DESHPANDE P A NAGWADE
Cerium vanadate (CeVO$_4$) and zirconium titanate (ZrTiO$_4$) powders have been synthesized by the dicarboxylate coprecipitation method.
The formation of precursors and mixed oxides was confirmed by their elementaland thermal analysis (thermogravimetric analysis–differential
thermal analysis), infrared spectroscopy (Fourier transform infrared), X-ray fluorescence spectroscopy, energy-dispersive X-ray analysis
and powder X-ray diffraction. X-ray analysis reveals the formation of a single-phasic CeVO$_4$ with tetragonal structure and ZrTiO$_4$ with
orthorhombic structure. The morphological characteristics of these oxides were studied by field-emission scanning electron microscopy
and a laserbased particle size analyzer. Different solid content and dispersants have been used to prepare various suspensions of these oxides
in distilled water and ethanol. The rheological flow behaviour of the suspensions has been studied by measuring their viscosity against
the increasing shear rate. The power-law model is applied to calculate consistency coefficient (
Volume 46, 2023
All articles
Continuous Article Publishing mode
Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
Chemical Sciences 2020
Prof. Surajit Dhara — School of Physics, University of Hyderabad, Hyderabad
Physical Sciences 2020
Click here for Editorial Note on CAP Mode
© 2022-2023 Indian Academy of Sciences, Bengaluru.