@article { ISI:000227550500009, title = {Co-precipitation method for the preparation of nanocrystalline ferroelectric SrBi2Nb2O9 ceramics}, journal = {Journal of Electroceramics}, volume = {14}, number = {1}, year = {2005}, month = {JAN}, pages = {83-87}, publisher = {SPRINGER}, type = {Article}, address = {VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS}, abstract = {

A simple co-precipitation technique had been successfully applied for the preparation of pure ultrafine single phase SrBi2Nb2O9. Ammonium hydroxide and ammonium oxalate were used to precipitate Sr2+, Bi3+ and Nb5+ cations simultaneously. No pyrochlore phase was found while heating powder at 850 C and pure SrBi2Nb2O9 (SBN) phase was formed as revealed by the X-ray diffraction (XRD) studies. Particle size and morphology was studied by transmission electron microscopy (TEM). The room temperature dielectric constant at 1 kHz is 100. The ferroelectric hysteresis loop parameters of these samples were also studied.

}, keywords = {Ceramics, Chemical synthesis, electronic materials, ferroelectricity, Oxides}, issn = {1385-3449}, doi = {10.1007/s10832-005-6588-y}, author = {Gaikwad, S. P. and Dhage, S. R. and Potdar, H. S. and Samuel, V. and Ravi, V.} } @article { ISI:000228797100048, title = {Preparation of ferroelectric BaNb2O6 the urea method}, journal = {Materials Letters}, volume = {59}, number = {14-15}, year = {2005}, month = {JUN}, pages = {1929-1931}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

A precipitate was formed when an aqueous solution of BaCl2, NbF5 and urea in required ratio (the ratio of total metal cations to the urea is five) is heated on a water bath at 100 degrees C. This precipitate on decomposition at 600 degrees C yielded the nanocrystallites of BaNb2O6 (BN), as confirmed by X-ray diffraction study (XRD). This is a much lower temperature as compared to that prepared by traditional solid state method (1000 degrees C) as reported for the formation of BaNb2O6. Transmission electron microscope (TEM) investigations revealed that the average particle size is 85 nm for the calcined powders. The room temperature dielectric constant at 1 kHz is found to be 900. The ferroelectric hysteresis loop parameters of these samples were also studied. (c) 2005 Elsevier B.V. All rights reserved.

}, keywords = {Ceramics, Chemical synthesis, electronic material, ferroelectricity, Oxides}, issn = {0167-577X}, doi = {10.1016/j.matlet.2005.02.028}, author = {Dhage, S. R. and Pasricha, R. and Ravi, V.} } @article { ISI:000230275100032, title = {Synthesis of bismuth oxide nanoparticles at 100 degrees C}, journal = {Materials Letters}, volume = {59}, number = {19-20}, year = {2005}, month = {AUG}, pages = {2523-2525}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

A simple gel to crystal conversion route has been followed for the preparation of ultrafine Bi2O3 particles at 80-100 degrees C under refluxing conditions. Freshly prepared bismuth hydroxide gel is allowed to crystallize under refluxing and stirring conditions for 6-12 h. Formation of nanocrystallites of Bi2O3 is confirmed by X-ray diffraction (XRD) study. The thermal decomposition of bismuth hydroxide yields Bi2O3 only at 400 degrees C. This shows the advantage of the present method. Transmission electron microscope (TEM) investigations revealed that the average particle size is 50 nm for these oven-dried powders. (c) 2005 Elsevier B.V All rights reserved.

}, keywords = {Ceramics, Chemical synthesis, Electron microscopy, Oxides, X-ray diffraction}, issn = {0167-577X}, doi = {10.1016/j.matlet.2005.03.037}, author = {Patil, M. M. and Deshpande, V. V. and Dhage, S. R. and Ravi, V.} } @article { ISI:000226803200008, title = {Synthesis of fine particles of ZnO at 100 degrees C}, journal = {Materials Letters}, volume = {59}, number = {7}, year = {2005}, month = {MAR}, pages = {779-781}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

A simple gel to crystal conversion route has been followed for the preparation of fine ZnO at 80-100 degreesC under refluxing conditions. Freshly prepared zinc hydroxide gel is allowed to crystallize under refluxing and stirring conditions for 4-6 It. Formation of fine crystallites of ZnO is confirmed by X-ray diffraction (XRD) study. Transmission electron microscope (TEM) investigations revealed that the average particle size is 100 nm for these powders. (C) 2004 Elsevier B.V All rights reserved.

}, keywords = {Ceramics, Chemical synthesis, Electron microscopy, Oxides, X-ray diffraction}, issn = {0167-577X}, doi = {10.1016/j.matlet.2004.11.019}, author = {Dhage, S. R. and Pasricha, R. and Ravi, V.} } @article { ISI:000228510500005, title = {Synthesis of nanocrystalline Mn3O4 at 100 degrees C}, journal = {Materials Research Bulletin}, volume = {40}, number = {4}, year = {2005}, month = {APR}, pages = {605-609}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

A simple gel to crystal conversion route has been followed for the preparation of nanocrystalline tetragonal Mn3O4 powders at 80-100 degrees C under refluxing conditions. Freshly prepared manganese hydroxide gel is allowed to crystallize under refluxing and stirring conditions for 4-6 h. Formation of nano crystallites of Mn3O4 is confirmed by X-ray diffraction (XRD) study. Transmission electron microscope (TEM) investigations revealed that the average particle size is 50 nm for these powders. (c) 2005 Elsevier Ltd. All rights reserved.

}, keywords = {Ceramics, Chemical synthesis, Electron microscopy, Oxides, X-ray diffraction}, issn = {0025-5408}, doi = {10.1016/j.materresbull.2005.01.009}, author = {Anilkumar, Mettu and Ravi, V.} } @article { ISI:000230338900015, title = {Synthesis of rutile from ATO and stearic acid}, journal = {Materials Letters}, volume = {59}, number = {21}, year = {2005}, month = {SEP}, pages = {2673-2675}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Nanocrystalline titanium dioxide in the rutile phase has been obtained from the solid state reaction between ammonium titanyl oxalate (ATO) and stearic acid at 400 degrees C in air. The fine powders of ATO and stearic acid are mixed well using acetone in an agate mortar and pestle for 2 h. This mixture (weight ratio of ATO to stearic acid \> 5) on heating at 400 degrees C produces rutile powders. For the ratios of ATO to stearic acid \< 5, a mixture of anatase and rutile phases is obtained. Pure ATO yields anatase phase on decomposition at 400 degrees C. These powders were characterized by X-ray diffraction (XRD), BET surface area measurements and transmission electron microscopy (TEM) studies. (c) 2005 Elsevier B.V. All rights reserved.

}, keywords = {Ceramics, Chemical synthesis, Electron microscopy, Oxides, X-ray techniques}, issn = {0167-577X}, doi = {10.1016/j.matlet.2005.04.016}, author = {Patil, M. M. and Deshpande, V. V. and Deshpande, S. B. and Samuel, V. and Ravi, V.} } @article { ISI:000227164000044, title = {Synthesis of Sr0.5Ba0.5Nb2O6 by urea method}, journal = {Materials Letters}, volume = {59}, number = {8-9}, year = {2005}, month = {APR}, pages = {1053-1055}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

A precipitate was formed when an aqueous solution of SrCl2, BaCl2, NbF5 and urea in stoichiometric ratio (total metal cations to urea ratio is 5) is heated on a water bath.. This precipitate on decomposition at 750 degreesC yielded the nanocrystallites of ternary oxide, Sr0.5Ba0.5Nb2O6 (SBN) as confirmed by X-ray diffraction study (XRD). This is much lower temperature as compared to that prepared by traditional solid state method (1000 degreesC as reported for the formation of SBN ceramics. Transmission electron microscope (TEM) investigations revealed that the average particle size is 100 nm for the calcined powders. The room temperature dielectric constant at 1 kHz is found to be 1050. The ferroelectric hysteresis loop parameters of these samples were also studied. (C) 2004 Elsevier B.V. All rights reserved.

}, keywords = {Ceramics, Electron microscopy, ferroelectricity, Oxides}, issn = {0167-577X}, doi = {10.1016/j.matlet.2004.12.003}, author = {Dhage, S. R. and Pasricha, R. and Ravi, V.} } @article { ISI:000238298100027, title = {Co-precipitation technique for the preparation of ferroelectric BaBi2Ta2O9}, journal = {Materials Chemistry and Physics}, volume = {98}, number = {2-3}, year = {2006}, month = {AUG}, pages = {344-346}, publisher = {ELSEVIER SCIENCE SA}, type = {Article}, address = {PO BOX 564, 1001 LAUSANNE, SWITZERLAND}, abstract = {

A simple co-precipitation technique had been successfully applied for the preparation of pure ultrafine single phase BaBi2Ta2O9 (BBT). Ammonium hydroxide and ammonium oxalate were used to precipitate Ba2+, Bi3+ and Ta5+ cations simultaneously. No pyrochlore phase was found while heating powder at 800 degrees C and pure BaBi2Ta2O9 phase was found to be formed by X-ray diffraction. Particle size and morphology was studied by transmission electron spectroscopy (TEM). The room temperature dielectric constant at 1 kHz is 350. The ferroelectric hysteresis loop parameters of these samples were also studied. (c) 2005 Elsevier B.V. All rights reserved.

}, keywords = {Ceramics, Chemical synthesis, electronic material, ferroelectricity, Oxides}, issn = {0254-0584}, doi = {10.1016/j.matchemphys.2005.09.036}, author = {Dhage, S. R. and Pasricha, R. and Murugan, A. Vadivel and Ravi, V.} } @article { ISI:000238866300004, title = {Coprecipitation technique to prepare Sr0.5Ba0.5Nb2O6}, journal = {Bulletin of Materials Science}, volume = {29}, number = {3}, year = {2006}, month = {JUN}, pages = {221-223}, publisher = {INDIAN ACADEMY SCIENCES}, type = {Article}, address = {C V RAMAN AVENUE, SADASHIVANAGAR, P B \#8005, BANGALORE 560 080, INDIA}, abstract = {

An aqueous mixture of ammonium oxalate and ammonium hydroxide was used to coprecipitate barium and strontium ions as oxalates and niobium ions as hydroxide under basic conditions. This precursor on calcining at 750 degrees C yielded Sr0.5Ba0.5Nb2O6 phase. This is a much lower temperature than that prepared by traditional solid state method (1000 degrees C) as reported for the formation of Sr0.5Ba0.5Nb2O6 (SBN). Transmission electron microscopic (TEM) investigations revealed that the average particle size was 80 nm for the calcined powders. The room temperature dielectric constant at I kHz was found to be 1100. The ferroelectric hysteresis loop parameters of these samples were also studied.

}, keywords = {Ceramics, Electron microscopy, ferroelectricity, Oxides, X-ray diffraction}, issn = {0250-4707}, doi = {10.1007/BF02706488}, author = {Murugan, A. Vadivel and Gaikwad, A. B. and Samuel, V. and Ravi, V.} } @article { ISI:000237158200003, title = {Phase evolution of NiTiO3 prepared by coprecipitation method}, journal = {Materials Letters}, volume = {60}, number = {15}, year = {2006}, month = {JUL}, pages = {1791-1792}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

A simple coprecipitation technique was used for the preparation of NiTiO3 powders. Ammonium carbonate solution was added to a solution mixture containing stoichiometric amounts of Ni(NO3)(2) and TiOCl2 to precipitate nickel as carbonate and titanium as hydroxide under basic conditions. The precipitate was calcined at different temperatures ranging from 100 to 800 degrees C and phase evolution of NiTiO3 was investigated by X-ray diffraction (XRD) studies. It is observed that nickel titanate was formed at 750 degrees C. For comparison, NiTiO3 was also prepared by standard ceramic process. Particle size and morphology was studied by transmission electron microscopy (TEM). (c) 2005 Elsevier B.V. All fights reserved.

}, keywords = {Ceramics, Chemical synthesis, Electron microscopy, NiTiO3, Oxides, X-ray diffraction}, issn = {0167-577X}, doi = {10.1016/j.matlet.2005.12.023}, author = {Murugan, A. Vadivel and Samuel, V. and Navale, S. C. and Ravi, V.} } @article { ISI:000244008300030, title = {Co-precipitation technique to prepare BaTa2O6}, journal = {Ceramics International}, volume = {33}, number = {2}, year = {2007}, month = {JAN}, pages = {297-299}, publisher = {ELSEVIER SCI LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {

A mixture of ammonium oxalate and ammonium hydroxide was used to co-precipitate barium and tantalum ions as barium oxalate and tantalum hydroxide under basic conditions. On calcination at 750 degrees C, this precursor yielded BaTa2O6 (BT) ceramics. This is much lower temperature as compared to that prepared by traditional solid-state method (1000 degrees C) as reported for the formation of BaTa206. Transmission electron microscope (TEM) investigations revealed that the average particle size is 70 nm for the calcined powders. The room temperature dielectric constant at 1 kHz is found to be 100. (c) 2005 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

}, keywords = {barium tantalate, Ceramics, Electron microscopy, Oxides, X-ray diffraction}, issn = {0272-8842}, doi = {10.1016/j.ceramint.2005.08.012}, author = {Navale, S. C. and Samuel, Violet and Gaikwad, A. B. and Ravi, V.} } @article { ISI:000246158300001, title = {Coprecipitation technique to prepare CoTa2O6 and CoNb2O6}, journal = {Materials Letter}, volume = {61}, number = {11-12}, year = {2007}, month = {MAY}, pages = {2127-2129}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

An aqueous solution of sodium hydroxide was used to coprecipitate cobalt and tantalum (or niobium) ions from their precursors as hydroxides under basic conditions. This precipitate yielded CoTa2O6 (CT) or CoNb2O6 (CN) ceramics on calcining at 700 degrees C, i.e. at a temperature much lower than 900 degrees C, reported for the formation of these powders prepared by the traditional solid state method. The X-ray diffraction (XRD) studies were employed to investigate phase contents and lattice parameters. The morphology of the synthesized powders was investigated by transmission electron microscopy (TEM). (c) 2006 Elsevier B.V. All rights reserved.

}, keywords = {Chemical synthesis, electronic materials, Oxides, X-ray methods}, issn = {0167-577X}, doi = {10.1016/j.matlet.2006.08.024}, author = {Mulla, Imtiaz S. and Natarajan, N. and Gaikwad, A. B. and Samuel, V. and Guptha, U. N. and Ravi, V.} } @article { ISI:000246158300058, title = {Coprecipitation technique to prepare NiNb2O6}, journal = {Materials Letter}, volume = {61}, number = {11-12}, year = {2007}, month = {MAY}, pages = {2354-2355}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

A mixture of ammonium carbonate and ammonium hydroxide was used to coprecipitate nickel and niobium ions as nickel carbonate and niobium hydroxide under basic conditions. This precursor yielded NiNb2O6 (NN) ceramics on calcining at 700 degrees C (at a temperature lower than 800 degrees C which is necessary for the formation of NiNb2O6 when prepared by the traditional solid state method). The average particle size and morphology of these powders were investigated by transmission electron microscope (TEM). (c) 2006 Elsevier B.V. All rights reserved.

}, keywords = {Chemical synthesis, Electron microscopy, electronic materials, Oxides, X-ray methods}, issn = {0167-577X}, doi = {10.1016/j.matlet.2006.09.010}, author = {Samuel, V. and Gaikwad, A. B. and Jadhav, A. D. and Natarajan, N. and Ravi, V.} } @article { ISI:000246260000011, title = {Preparation of nanocrystalline ferroelectric CaBi4Ti4O15 by citrate gel method}, journal = {Ceramics International}, volume = {33}, number = {4}, year = {2007}, month = {JAN}, pages = {569-571}, publisher = {ELSEVIER SCI LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {

A gel was formed when an aqueous solution of CaCl2, BiNO3, TiOCl2 and citric acid in stoichiometric ratio is heated on a water bath. This gel on decomposition at 700 degrees C produced nano crystallites of the ternary oxide, CaBi4Ti4O15 (CBT). The phase contents and lattice parameters were studied by the powder X-ray diffraction (XRD). Particle size and morphology was studied by transmission electron spectroscopy (TEM). The room temperature dielectric constant at 1 kHz is 390. The ferroelectric hysteresis loop parameters of these samples were also studied by a home-built Sawyer-tower circuit. (c) 2006 Elsevier Ltd and Techna Group S.H. All rights reserved.

}, keywords = {Ceramics, Chemical synthesis, Electron microscopy, Oxides, X-ray methods}, issn = {0272-8842}, doi = {10.1016/j.ceramint.2005.11.006}, author = {Murugan, A. Vadivel and Gaikwad, A. B. and Samuel, V. and Ravi, V.} } @article { ISI:000248175000038, title = {Synthesis of La0.7Sr0.3MnO3 at 800 degrees C using citrate gel method}, journal = {Ceramics International}, volume = {33}, number = {6}, year = {2007}, month = {AUG}, pages = {1129-1132}, publisher = {ELSEVIER SCI LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {

Manganite systems have been of considerable interest in the recent past due to their potential to operate in wide property range and also to serve as effective magnetic sensing and storing devices when synthesized using stringent conditions. We report a novel citrate gel method, in which La0.7Sr0.3MnO3 system has been synthesized at temperature 800 degrees C (LSMO800) with the synthesis duration is 6 h. The results have been compared with the sample synthesized at 1050 degrees C (LSMO1050). The synthesized bulk polycrystalline sample shows single-phase nature with the increase in particle size from similar to 50 nm to 300 nm with the increase in the sintering temperature. The magnetization data for LSMO800 shows well-defined hysteresis with saturation magnetization at around 1800 Oe and Curie temperature at 360 K, which is slightly lower than that of LSMO1050, which is 375 K. The results can be well attributed to the grain boundary effects. (C) 2006 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

}, keywords = {Ceramics, Citrate gel method, CMR, Oxides}, issn = {0272-8842}, doi = {10.1016/j.ceramint.2006.02.008}, author = {Ravi, V. and Kulkarni, S. D. and Samuel, V. and Kale, Sangeeta N. and Mona, J. and Rajgopal, R. and Daundkar, A. and Lahoti, P. S. and Joshi, Rakesh S.} } @article { ISI:000244008300031, title = {Varistors based on Ta-doped TiO2}, journal = {Ceramics International}, volume = {33}, number = {2}, year = {2007}, month = {MAR}, pages = {301-303}, publisher = {ELSEVIER SCI LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {

The nonlinear current (I)-voltage (V) characteristics of titanium dioxide are examined when doped with small quantities (0.05-0.5 at.\%) of tantalum pentaoxide. For optimum compositions, the nonlinear coefficients are found to be in the range of 25-30 and the breakdown field strength (EB) is similar to 4000 V/cm. The obtained alpha- and E-B-values are higher than the previously reported values for TiO2 ceramics. The acceptor like surface states at the grain boundary adsorb oxygen during sintering and cooling, leading to formation of grain boundary barrier. The grain boundary barrier height (OB) is calculated using Schottky equation. (c) 2005 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

}, keywords = {Ceramics, Oxides, Schottky barrier, TiO2, varistor}, issn = {0272-8842}, doi = {10.1016/j.ceramint.2005.07.026}, author = {Navale, S. C. and Murugan, A. Vadivel and Ravi, V.} } @article { ISI:000254698300035, title = {Co-precipitation method for preparation of Bi3TiNbO9 powders}, journal = {Ceramics International}, volume = {34}, number = {3}, year = {2008}, month = {APR}, pages = {675-677}, publisher = {ELSEVIER SCI LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {

A simple co-precipitation technique has been successfully used for the preparation of pure, ultrafine, single phase Bi3TiNbO9 (BTN). An aqueous ammonium hydroxide solution was used to simultaneously precipitate Bi3+, Ti4+ and Nb5+, cations as hydroxides under basic conditions (pH similar to 9). No pyrochlore phase was found while heating powder at 500 degrees C and pure BTN phase was found to be formed by X-ray diffraction (XRD). For comparison, BTN samples were also synthesized by the traditional solid state method. The sequence of phase formation in both cases were investigated by XRD studies. (c) 2007 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

}, keywords = {Ceramics, Chemical synthesis, electronic material, Oxides, XRD}, issn = {0272-8842}, doi = {10.1016/j.ceramint.2007.02.002}, author = {Gupta, U. N. and Samuel, V. and Muthurajan, H. and Kumar, H. H. and Patil, S. D. and Ravi, V.} } @article { ISI:000257538200034, title = {Co-precipitation technique to prepare BiNbO4 powders}, journal = {Ceramics International}, volume = {34}, number = {6}, year = {2008}, month = {AUG}, pages = {1565-1567}, publisher = {ELSEVIER SCI LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {

A simple co-precipitation technique was successfully used for the preparation of pure ultrafine single phase BiNbO4. A standard ammonium hydroxide solution was used to precipitate Bi3+ and Ta5+ cations as hydroxides simultaneously under basic conditions. For comparison, BN powders were also prepared by the traditional solid-state method. It is observed that the co-precipitation technique produces BiNbO4 on heating at 600 degrees C, whereas complete phase formation occurs only at 800 degrees C in the solid-state method. The phase contents and lattice parameters were Studied by powder X-ray diffraction (XRD). (C) 2007 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

}, keywords = {BiNbO4, Ceramics, Chemical synthesis, Electron microscopy, Oxides, X-ray diffraction}, issn = {0272-8842}, doi = {10.1016/j.ceramint.2007.03.022}, author = {Radha, R. and Gupta, U. N. and Samuel, V. and Muthurajan, H. and Kumar, H. H. and Ravi, V.} } @article { ISI:000252408000041, title = {Co-precipitation technique to prepare BiTaO4 powders}, journal = {Materials Letters}, volume = {62}, number = {3}, year = {2008}, month = {FEB}, pages = {501-503}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

A simple co-precipitation technique has been successfully used for the preparation of pure ultrafine single phase BiTaO4. A standard ammonium hydroxide solution was used to precipitate Bi3+ and Ta5+ cations as hydroxides simultaneously under basic conditions. This precursor, on heating at 600 degrees C, produced product phase. This is the lowest temperature for the formation of BiTaO4 phase so far reported in the literature. For comparison BiTaO4 powders were also prepared by the traditional solid state method. The phase contents and lattice parameters were studied by the powder X-ray diffraction (XRD). (c) 2007 Elsevier B.V. All rights reserved.

}, keywords = {BiTaO4, Ceramics, Chemical synthesis, Electron microscopy, Oxides, X-ray diffraction}, issn = {0167-577X}, doi = {10.1016/j.matlet.2007.05.074}, author = {Muthurajan, H. and Gupta, U. N. and Rituraj, B. and Rao, N. Koteswara and Pradhan, Sivaram and Radha, R. and Ravi, V.} } @article { ISI:000254820000016, title = {La0.67Ce0.03Sr0.3MnO3-coupled microwave assisted ultra-fast synthesis of nanocrystalline cobalt oxide and Bismuth oxide}, journal = {Materials Letters}, volume = {62}, number = {10-11}, year = {2008}, month = {APR}, pages = {1511-1513}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Bismuth hydroxide and Cobalt hydroxide gels were freshly prepared by adding aqueous sodium hydroxide to their corresponding nitrates under basic conditions. Then they were oven dried at 373 K and found to be amorphous in X-ray diffraction (XRD) study. They crystallized into their respective oxides by microwave irradiation (2.45 GHz) in merely 2 min using La0.67Ce0.03Sr0.3MnO3 (LCSMO) as couplant in a microwave domestic oven (similar to 100 W). This is the lowest temperature treatment and synthesis time so far reported in the literature for the formation of these systems. Formation of nanocrystallites of Bi2O3 (10 nm) and Co3O4 (15 nm) has been confirmed by XRD. Normally these hydroxides produce oxides only on heating at temperature \>673 K or digesting them at 373 K for 4 - 6 hours as reported by us earlier. Microwave assisted heating proves to be a novel technology whose applications can be carefully harnessed due to its unique effects compared to the conventional heating, such as rapid volumetric heating, shortened reaction time and energy saving. (C) 2007 Elsevier B.V. All rights reserved.

}, keywords = {Citrate gel method, Manganites, Microwave, Oxides}, issn = {0167-577X}, doi = {10.1016/j.matlet.2007.09.013}, author = {Rajagopal, Rajashree and Mona, J. and Joshi, Rakesh S. and Kale, Sangeeta N. and Pradhan, Sivararn and Gaikwad, A. B. and Ravi, V.} } @article { ISI:000257367100016, title = {Low temperature synthesis and characterization of BiNbO4 powders}, journal = {Materials Characterization}, volume = {59}, number = {8}, year = {2008}, month = {AUG}, pages = {1083-1087}, publisher = {ELSEVIER SCIENCE INC}, address = {360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA}, abstract = {

BiNbO4 powders, a potential microwave dielectric ceramic were prepared by both coprecipitation and solid state techniques. In the former method, an aqueous ammonium hydroxide was used to precipitate Bi3+ and Ta5+ cations as hydroxides simultaneously under basic conditions. It is observed that the co-precipitation produces BiNbO4 phase on heating at 600 degrees C, whereas complete phase formation occurs only at 800 degrees C in the case of solid state method. The phase contents and lattice parameters were studied by powder X-ray diffraction. The sequence of the reaction and phase evolution of BiNbO4 were also studied by the X-ray diffraction. The samples were characterized by the differential-thermal/thermo-gravimetric analyses and scanning electron microscopy techniques. (C) 2007 Elsevier Inc. All rights reserved.

}, keywords = {BiNbO4, Ceramics, Chemical synthesis, Electron microscopy, Oxides, X-ray diffraction}, issn = {1044-5803}, doi = {10.1016/j.matchar.2007.08.026}, author = {Radha, R. and Muthurajan, H. and Rao, N. Koteswara and Pradhan, Sivaram and Gupta, U. N. and Jha, Ratnesh Kumar and Mirji, S. A. and Ravi, V.} } @article { ISI:000251870400005, title = {Microwave assisted low temperature rapid synthesis of manganite system using La0.67Ce0.03Sr0.3MnO3 mini-cavity furnace}, journal = {Materials Letters}, volume = {62}, number = {2}, year = {2008}, month = {JAN}, pages = {191-193}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Amorphous La0.7Sr0.3MnO3 (LSMO) and La0.7Ca0.3MnO3 (LCMO) precursor powders synthesized by the citrate gel method at 673 K, have been found to crystallize by microwave irradiation in just 60 s using La0.67Ce0.03Sr0.3MnO3 (Ce-LSMO) as couplant. This is the lowest temperature treatment and synthesis time so far reported in literature for the fort-nation of manganite systems. Using ceramic route, the same amorphous samples crystallize on heat treatment only at temperatures greater than 1000 K. The microwave heating through this method is novel and has tremendous potential for accelerating the evolution of the product phase in very shorter durations, with just low temperature processing of the precursors, which cannot be realized in normal process. (c) 2007 Elsevier B.V. All rights reserved.

}, keywords = {Citrate gel method, LSMO, Manganites, Microwave, Oxides}, issn = {0167-577X}, doi = {10.1016/j.matlet.2007.05.002}, author = {Kale, Sangeeta N. and Rajagopal, Rajashree and Mona, J. and Londhe, D. P. and Joshi, Rakesh S. and Jagadale, Tushar C. and Satyanarayana, C. and Ravi, V.} } @article { ISI:000257365900027, title = {Novel hydroxide precursors for low temperature synthesis of selected ternary oxides}, journal = {Materials Research Bulletin}, volume = {43}, number = {7}, year = {2008}, month = {JUL}, pages = {1842-1849}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

A novel method of using hydroxide precursors to reduce the synthesis temperature for few selected ternary oxides has been presented here. This technique is very useful and advantageous when the ternary oxides contain an alkaline earth element. The selected compositions for this method are BaCeO3 (BC), BaBiO3 (BB), La0.7Sr0.3CoO3 (LSCO) and BaBi2Nb2O9 (BBN). Commercially purchased strontium (or barium) hydroxide and freshly prepared lanthanum, cobalt, bismuth and niobium hydroxides were mixed thoroughly in stoichiometric ratio and heated at different temperatures ranging from 100 to 700 degrees C for 10 h for corresponding compositions. The sequence of the reaction and evolution of the product phase were studied by the X-ray diffraction (XRD) studies. The phase purity and lattice parameters were also determined by XRD investigations. All the product phases in each case were formed at relatively low temperature than when they were prepared by co-precipitation or solid state method. The morphology and average particle size of these powders were investigated by scanning electron microscopy (SEM). (C) 2007 Elsevier Ltd. All rights reserved.

}, keywords = {Ceramics, Chemical synthesis, Electron microscopy, Oxides, X-ray diffraction}, issn = {0025-5408}, doi = {10.1016/j.materresbull.2007.07.006}, author = {Muthurajan, H. and Rao, N. Koteswara and Gupta, U. N. and Pradhan, Sivaram and Jha, Ratnesh Kumar and Kumar, H. H. and Mirji, S. A. and Ravi, V.} } @article { ISI:000255612400002, title = {Preparation of ferroelectric CaBi(4)Ti(4)O(15) powders from novel hydroxide precursors}, journal = {Materials Letters}, volume = {62}, number = {12-13}, year = {2008}, month = {APR}, pages = {1751-1753}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Ferroelectric CaBi(4)Ti(4)O(15) (CBT) powders were prepared for the first time from their respective hydroxides. Commercially purchased Ca(OH)(2) is mixed thoroughly with freshly prepared Bi(OH)(3) and Ti(OH)(4) in stoichiometrie ratio and heated at different temperatures ranging from 100 to 600 degrees C. The CBT phase found to be formed at 500 degrees C by the X-ray diffraction studies. This is the lowest temperature so far reported in the literature for the formation of CBT phase. The advantage of this method is that it also avoids the formation of calcium carbonate phase during synthesis. The phase contents and lattice parameters were studied by the powder X-ray diffraction (XRD) method. The average particle size and morphology were studied by scanning electron microscopy (SEM) technique. (c) 2007 Elsevier B.V All rights reserved.

}, keywords = {CaBi(4)Ti(4)O(15), Ceramics, Chemical synthesis, Electron microscopy, Oxides, X-ray methods}, issn = {0167-577X}, doi = {10.1016/j.matlet.2007.09.080}, author = {Deshmukh, Rupali G. and Vaishampayan, Mukta V. and Darshane, Sonali L. and Mulla, Imtiaz S. and Gaikwad, A. B. and Rao, N. Kotaserwara and Ravi, V.} } @article { ISI:000252408000048, title = {Synthesis of LSMO at low temperature by novel hydroxide precursor technique}, journal = {Materials Letters}, volume = {62}, number = {3}, year = {2008}, month = {FEB}, pages = {527-529}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

A novel technique of mixing individual hydroxide is employed to prepare La0.65Sr0.35MnO3 (LSMO) at low temperature. Freshly prepared lanthanum and manganese hydroxides are mixed thoroughly with strontium hydroxide in stoichiometric ratio and heated at different temperatures ranging from 100 to 500 degrees C for 6 h. At 500 degrees C, formation of La0.65Sr0.35MnO3 was confirmed by the X-ray diffraction studies (XRD). This is the lowest temperature so far reported in the literature. The particle size and morphology were investigated by scanning electron microscopy (SEM). (c) 2007 Elsevier B.V. All rights reserved.

}, keywords = {Ceramics, Electron microscopy, La0.65Sr0.35MnO3, Oxides, Precipitation, X-ray diffraction}, issn = {0167-577X}, doi = {10.1016/j.matlet.2007.05.077}, author = {Gupta, U. N. and Muthurajan, H. and Kumar, H. H. and Rao, N. Koteswara and Gokhale, Suresh P. and Ravi, V.} }