@article { ISI:000227603500004, title = {Co-precipitation method for the preparation of fine ferroelectric BaBi2M2O9}, journal = {Ceramics International}, volume = {31}, number = {3}, year = {2005}, month = {JAN}, pages = {379-381}, publisher = {ELSEVIER SCI LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {

A simple co-precipitation technique had been successfully applied for the preparation of pure fine powders of single phase BaBi2Nb2O9. Ammonium hydroxide and ammonium oxalate were used to precipitate Ba2+, Bi3+ and Nb5+ cations simultaneously. No pyrochlore phase was formed while heating powder at 800 degrees C and pure BaBi2Nb2O9 phase was found to be formed by X-ray diffraction (XRD). Particle size and morphology was studied by transmission electron spectroscopy (TEM). The room temperature dielectric constant at 1 kHz is 100. The ferroelectric hysteresis loop parameters of these samples were also studied. (c) 2004 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

}, keywords = {dielectric properties, Electron microscopy, ferroelectric properties, powders chemical preparation}, issn = {0272-8842}, doi = {10.1016/j.ceramint.2004.05.024}, author = {Gaikwad, S. P. and Potdar, HS and Samuel, V and Ravi, V} } @article { ISI:000227447800012, title = {Coprecipitation technique to prepare BaNb2O6}, journal = {Materials Science and Engineering B-Solid State Materials for Advanced Technology}, volume = {117}, number = {2}, year = {2005}, month = {MAR}, pages = {169-171}, publisher = {ELSEVIER SCIENCE SA}, type = {Article}, address = {PO BOX 564, 1001 LAUSANNE, SWITZERLAND}, abstract = {

A mixture of ammonium oxalate and ammonium hydroxide was used to coprecipitate barium and niobium ions as barium oxalate and niobium hydroxide under basic conditions. This precursor on calcination at 750degreesC yielded BaNb2O6 ceramics. This is a much lower temperature as compared to that prepared by traditional solid-state method (1000degreesC), as reported for the formation of BaNb2O6. 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 1100. The ferroelectric hysteresis loop parameters of these samples were also studied. (C) 2004 Elsevier B.V. All rights reserved.

}, keywords = {Ammonia, Ceramics, Electron microscopy, niobium oxide, Oxides}, issn = {0921-5107}, doi = {10.1016/j.mseb.2004.11.009}, author = {Natarajan, N and Samuel, V and Pasricha, R and Ravi, V} } @article { ISI:000237439300005, title = {Coprecipitation technique to prepare NaNbO3 and NaTaO3}, journal = {Bulletin of Materials Science}, volume = {29}, number = {2}, year = {2006}, month = {APR}, pages = {123-125}, publisher = {INDIAN ACADEMY SCIENCES}, type = {Article}, address = {C V RAMAN AVENUE, SADASHIVANAGAR, P B \#8005, BANGALORE 560 080, INDIA}, abstract = {

A simple coprecipitation technique has been used successfully for the preparation of pure, ultrafine, single phases of NaNbO3 (NN) and NaTaO3 (NT). An alcoholic solution of ammonium carbonate and ammonium hydroxide was used to precipitate Na+ and Nb5+ (or Ta5+) cations under basic conditions as carbonate and hydroxide, respectively. On heating at 700 degrees C, these precursors produce respective products. For comparison, both NN and NT powders were also prepared by the traditional solid state method. The phase purity and lattice parameters were studied by powder X-ray diffraction (XRD). The particle size and morphology were studied by scanning electron microscopy (SEM).

}, keywords = {Ceramics, Chemical synthesis, Electron microscopy, electronic materials, Oxides, X-ray methods}, issn = {0250-4707}, doi = {10.1007/BF02704604}, author = {Samuel, V and Gaikwad, A. B. and Ravi, V} }