@article { ISI:000232347900014, title = {Synthesis of chromium substituted nano particles of cobalt zinc ferrites by coprecipitation}, journal = {Materials Letters}, volume = {59}, number = {27}, year = {2005}, month = {NOV}, pages = {3402-3405}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Nano particles of chromium substituted cobalt zinc ferrite have been synthesized by a chemical co-precipitation method. X-ray diffraction studies of the nano particles of CrxCo0.5-xZn0.5Fe2O4 (x = 0.1 to 0.5) heat-treated at 300 degrees C show that the particle sizes are in the range of 2 to 7 nm. Room temperature Fe-57 Mossbauer spectra of all the samples show only two doublets, confirming the presence of superparamagnetic relaxation in the nano particles. An exponential decrease in the superparamagnetic blocking temperature, with increasing chromium concentration, is observed for these samples. (C) 2005 Elsevier B.V. All rights reserved.

}, keywords = {Co0.5Zn0.5Fe2O4, Mossbauer spectroscopy, nano materials}, issn = {0167-577X}, doi = {10.1016/j.matlet.2005.06.004}, author = {Sharma, R. K. and Suwalka, O. and Lakshmi, N. and Venugopalan, K. and Banerjee, Abhik and Joy, Pattayil Alias} } @article { ISI:000235256200004, title = {Preparation of gamma-Fe2O3 nanoparticles using DC thermal arc-plasma route, their characterization and magnetic properties}, journal = {Scripta Materialia}, volume = {54}, number = {7}, year = {2006}, month = {APR}, pages = {1235-1240}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

gamma-Fe2O3 particles were prepared, for the first time, using a direct current thermal arc-plasma route. The powder was characterized using X-ray diffraction, Mossbauer spectroscopy, X-ray photoelectron spectroscopy, chemical analysis, vibrating sample magnetometry C and transmission electron microscopy. The high purity, stoichiometry and spherical morphology of the gamma-Fe2O3 particles (saturation magnetization = 79 emu g(-1) and coercivity = 348 Oe) were confirmed. (c) 2006 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

}, keywords = {chemical analysis, DC thermal arc-plasma route, maghemite, Mossbauer spectroscopy, XPS}, issn = {1359-6462}, doi = {10.1016/j.scriptamat.2005.12.029}, author = {Banerjee, Indrani and Khollam, Y. B. and Balasubramanian, C. and Pasricha, R. and Bakare, P. P. and Patil, K. R. and Das, A. K. and Bhoraskar, S. V.} } @article { ISI:000261061100016, title = {Magnetic and Mossbauer spectroscopic studies of NiZn ferrite nanoparticles synthesized by a combustion method}, journal = {Hyperfine Interactions}, volume = {183}, number = {1-3}, year = {2008}, month = {APR}, pages = {99-107}, publisher = {SPRINGER}, address = {VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS}, abstract = {

The properties of nanocrystalline Ni(0.5)Zn(0.5)Fe(2)O(4) synthesized by an auto-combustion method have been investigated by magnetic measurements and Mossbauer spectroscopy. The as-synthesized single phase nanosized ferrite powder is annealed at different temperatures in the range 673-1,273 K to obtain nanoparticles of different sizes. The powders are characterized by powder X-ray diffraction, vibrating sample magnetometer, transmission electron microscopy and Mossbauer spectroscopy. The as-synthesized powder with average particle size of similar to 9 nm is superparamagnetic. Magnetic transition temperature increases up to 665 K for the nanosized powder as compared to the transition temperature of 548 K for the bulk ferrite. This has been confirmed as due to the abnormal cation distribution, as evidenced from room temperature Mossbauer spectroscopic studies.

}, keywords = {Ferrite, magnetic properties, Mossbauer spectroscopy, Nanoparticles}, issn = {0304-3843}, doi = {10.1007/s10751-008-9736-3}, author = {Sreeja, V. and Vijayanand, S. and Deka, Sasanka and Joy, Pattayil Alias} } @article { ISI:000258965100011, title = {Mossbauer spectroscopic investigations of nanophase iron oxides synthesized by thermal plasma route}, journal = {Materials Characterization}, volume = {59}, number = {9}, year = {2008}, month = {SEP}, pages = {1215-1220}, publisher = {ELSEVIER SCIENCE INC}, address = {360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA}, abstract = {

Magnetic nanoparticles of iron oxide were synthesized by transferred arc plasma induced gas phase condensation method. Structural, morphological and magnetic studies of the as synthesized powder were carried out using X-ray diffraction, transmission electron microscopy and Mossbauer spectroscopy. These studies have revealed the simultaneous nucleation and condensation of different magnetic phases with a broad size distribution of the nanoparticles which is peaked at 30-50 nm and ranges from 10 nm to 80 nm. 57 Fe Mossbauer spectra recorded at various temperatures (5 K-300 K) in presence of external magnetic field (at 5 K) have suggested the presence of different phases of iron oxide with sizable amounts of gamma-Fe2O3 and alpha-Fe2O3 in addition to Fe3O4. The relative concentrations of these phases have been obtained by a self consistent spectral area analysis and were found to be 44:22:34 (\%). (C) 2007 Elsevier Inc. All rights reserved.

}, keywords = {iron oxides, Mossbauer spectroscopy, phase analysis, plasma synthesis}, issn = {1044-5803}, doi = {10.1016/j.matchar.2007.10.003}, author = {Nagar, Harshada and Kulkarni, Naveen V. and Karmakar, Soumen and Sahoo, B. and Banerjee, Indrani and Chaudhari, P. S. and Pasricha, R. and Das, A. K. and Bhoraskar, S. V. and Date, Sadgopal K. and Keune, W.} } @article { ISI:000293826800006, title = {Structural, magnetic and mossbauer spectral studies of nanocrystalline Ni0.5Zn0.5Fe2O4 ferrite powders}, journal = {Journal of Alloys and Compounds}, volume = {509}, number = {37}, year = {2011}, month = {SEP}, pages = {8999-9004}, publisher = {ELSEVIER SCIENCE SA}, address = {PO BOX 564, 1001 LAUSANNE, SWITZERLAND}, abstract = {

Nanocrystalline Ni0.5Zn0.5Fe2O4 powders, synthesized by a combustion method are investigated by X-ray diffraction, vibrating sample magnetometry and Mossbauer spectroscopic techniques. We adopt a strategy to systematically control the particle sizes between 4 and 45 nm simply by changing the elemental stoichiometric coefficient, Phi(e), of the combustion mixture. Curie temperature of the superparamagnetic particles of size 4 nm is higher than that of the bulk particles. Interestingly, bigger particles (45 nm) show a comparable room temperature saturation magnetization and exceptionally very high Curie temperature of 833 K, when compared to that of the bulk Ni0.5Zn0.5Fe2O4 material (563 K). (C) 2011 Elsevier B. V. All rights reserved.

}, keywords = {Chemical synthesis, Magnetisation, Mossbauer spectroscopy, Nanostructured materials}, issn = {0925-8388}, doi = {10.1016/j.jallcom.2011.06.047}, author = {Verma, Seema and Joy, Pattayil Alias and Kurian, Sajith} } @article { ISI:000313404400021, title = {Magnetic properties of nanocrystalline CoFe2O4 synthesized by thermal plasma in large scale}, journal = {Materials Chemistry and Physics}, volume = {137}, number = {2}, year = {2012}, month = {DEC}, pages = {586-595}, publisher = {ELSEVIER SCIENCE SA}, address = {PO BOX 564, 1001 LAUSANNE, SWITZERLAND}, abstract = {

The paper reports the large scale synthesis of nanoparticles of CoFe2O4 using thermal plasma reactor by gas phase condensation method. The yield of formation was found to be around 15 g h(-1). The magnetic properties of CoFe2O4, synthesized at different reactor powers, were investigated in view of studying the effect of operating parameters of plasma reactor on the structural reorganization leading to the different cation distribution. The values of saturation magnetization, coercivity and remanent magnetization were found to be influenced by input power in thermal plasma. Although the increase in saturation magnetization was marginal (61 emu g(-1) to 70 emu g(-1)) with increasing plasma power; a significant increase in the coercivity (552 Oe to 849 Oe) and remanent magnetization (16 emu g(-1) to 26 emu g(-1)) were also noticed. The Mossbauer spectra showed mixed spinel structure and canted spin order for the as synthesized nanoparticles. The detailed analysis of cation distribution using the Mossbauer spectroscopy and X-ray photoelectron spectroscopy leads to the conclusion that the sample synthesized at an optimized power shows the different site selective states. (C) 2012 Elsevier B.V. All rights reserved.

}, keywords = {Magnetic materials, magnetic properties, Mossbauer spectroscopy, Nanostructures}, issn = {0254-0584}, doi = {10.1016/j.matchemphys.2012.10.007}, author = {Nawale, A. B. and Kanhe, Nilesh S. and Patil, K. R. and Reddy, V. R. and Gupta, A. and Kale, B. B. and Bhoraskar, S. V. and Mathe, Vikas L. and Das, A. K.} } @article { ISI:000316024500022, title = {Synthesis of low coercive BaFe12O19 hexaferrite for microwave applications in low-temperature cofired ceramic}, journal = {Journal of Electronic Materials}, volume = {42}, number = {4}, year = {2013}, month = {APR}, pages = {761-768}, publisher = {SPRINGER}, address = {233 SPRING ST, NEW YORK, NY 10013 USA}, abstract = {

Polycrystalline M-type barium hexaferrite (BaFe12O19) samples have been synthesized by solution combustion route at different pH and calcination conditions in order to reduce the coercivity for microwave applications in low-temperature cofired ceramic (LTCC) substrates. Structural, morphological, and magnetic properties of BaFe12O19 were studied by x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Raman spectroscopy, vibrating sample magnetometry (VSM), and Mossbauer spectroscopy. The formation of a single-phase hexagonal structure was confirmed by XRD. The Raman spectra reveal all characteristic peaks of BaFe12O19, illustrating the phase purity and crystal lattice symmetry of the synthesized material. Mossbauer spectra illustrate the existence of Fe3+ cations at all five crystallographic lattice sites. The microstructural features observed by FESEM disclose the growth of nanoregime particles into hexagonal platelet particles after calcination at temperatures from 800A degrees C to 1200A degrees C. The VSM results show a lower coercivity (1350 Oe to 3500 Oe) together with reasonably high saturation magnetization (55 emu/g to 60 emu/g) and a high bulk resistivity (\> 10(9) Omega-cm) at room temperature. The dependence of magnetic and electrical properties on the preparation and processing conditions is also discussed.

}, keywords = {Barium hexaferrite, coercivity, LTCC, Mossbauer spectroscopy, Raman spectroscopy}, issn = {0361-5235}, doi = {10.1007/s11664-012-2398-6}, author = {Rane, Vivek A. and Meena, Sher Singh and Gokhale, Suresh P. and Yusuf, S. M. and Phatak, Girish J. and Date, Sadgopal K.} }