Ashok K Ganguli
Articles written in Journal of Chemical Sciences
Volume 112 Issue 3 June 2000 pp 374-374
Phase relations in Ag-Ni-Zn-S and Cu-Si-Ni-Sn-S systems
Volume 115 Issue 5-6 October 2003 pp 431-438
New perovskite-related oxides having high dielectric constant: Ln2Ba2CaZn2Ti3O14 (Ln = La and Pr)
Two new oxides, La2Ba2CaZn2Ti3O14 and Pr2Ba2CaZn2Ti3O14, have been synthesized by the ceramic route at 1100°C. These oxides crystallize in the disordered cubic structure with an ‘a’ lattice parameter of 3.9728 (2) and 3.9448 (5) respectively. These oxides show high dielectric constant (70 and 57) and low loss (0.003 and 0.013 at 100 kHz) for La2Ba2CaZn2Ti3O14 and Pr2Ba2CaZn2Ti3O14 respectively. The dielectric constant is highly stable with frequency and temperature.
Volume 118 Issue 1 January 2006 pp 37-42
A new form of MgTa2O6 obtained by the molten salt method
Ashok K Ganguli Shikha Nangia Meganathan Thirumal Pratibha L Gai
Using molten salt route (with NaCl/KCl as the salt) we have been able to synthesize a new form of magnesium tantalate at 850°C. Powder X-ray diffraction data could be indexed on an orthorhombic unit cell with lattice parameters, ‘
Volume 118 Issue 6 November 2006 pp 513-518
Tokeer Ahmad Kandalam V Ramanujachary Samuel E Lofland Ashok K Ganguli
Nanoparticles of complex manganites (viz. LaMnO3, La0.67Sr0.33MnO3 and La0.67Ca{0.33}MnO3) have been synthesized using the reverse micellar route. These manganites are prepared at 800‡C and the monophasic nature of all the oxides has been established by powder X-ray diffraction studies. TEM studies show an average grain size of 68, 80 and 50 nm for LaMnO3, La0.67Sr0.33MnO3 and La0.67Ca{0.33}MnO3respectively. Ferromagnetic ordering is observed at around 250 K for LaMnO3, 350 K for La0.67Sr0.33MnO3 and 200 K for La0.67Ca{0.33}MnO3. These Curie temperatures correspond well with those reported for bulk materials with similar composition.
Volume 120 Issue 6 November 2008 pp 521-528
Aparna Ganguly Rituparna Kundu Kandalam V Ramanujachary Samuel E Lofland Dipankar Dase N Y Vasanthacharya Tokeer Ahmad Ashok K Ganguli
Sub-micron rods and spheres of cobalt succinate sesquihydrate and iron succinate trihydrate/pentahydrate respectively have been synthesized by the reverse micellar route. These precursors are an excellent source for the synthesis of metal and metal oxide nanoparticles. Cubes of (edge length ∼ 150 nm) Fe3O4 and elongated particles of Fe2O3 (∼ diameter of 200 nm) were obtained. The role of oxidation state of the metal ion in controlling the morphology of the nanostructured dicarboxylates has been investigated. Rods with shorter length were obtained when longer chain dicarboxylate was used as ligand. Heating in nitrogen atmosphere also provided pure Co and 𝛼-Fe nanoparticles. The Fe nanoparticles show nearly 100% superparamagnetism. Temperature-dependent magnetic studies show a Morin-like transition for Fe2O3 nanoparticles at 223 K and the Verwey transition at 115 K for Fe3O4 nanoparticles. Co3O4 nanoparticles showed antiferromagnetic ordering at 20 K.
Volume 135, 2023
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