@article { ISI:000245291700016, title = {Finite size effects on the electrical properties of sol-gel synthesized CoFe2O4 powders: deviation from Maxwell-Wagner theory and evidence of surface polarization effects}, journal = {Journal of Physics D-Applied Physics}, volume = {40}, number = {6}, year = {2007}, month = {MAR}, pages = {1593-1602}, publisher = {IOP PUBLISHING LTD}, type = {Article}, address = {DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND}, abstract = {

Fine particles of cobalt ferrite were synthesized by the sol-gel method. Subsequent heat treatment at different temperatures yielded cobalt ferrites having different grain sizes. X-ray diffraction studies were carried out to elucidate the structure of all the samples. Dielectric permittivity and ac conductivity of all the samples were evaluated as a function of frequency, temperature and grain size. The variation of permittivity and ac conductivity with frequency reveals that the dispersion is due to Maxwell-Wagner type interfacial polarization in general, with a noted variation from the expected behaviour for the cold synthesized samples. High permittivity and conductivity for small grains were explained on the basis of the correlated barrier-hopping model.

}, issn = {0022-3727}, doi = {10.1088/0022-3727/40/6/001}, author = {George, Mathew and Nair, Swapna S. and Malini, K. A. and Joy, Pattayil Alias and Anantharaman, Maliemadom R.} } @article { ISI:000264092400030, title = {Impact of zinc substitution on the structural and magnetic properties of chemically derived nanosized manganese zinc mixed ferrites}, journal = {Journal of Magnetism and Magnetic Materials}, volume = {321}, number = {8}, year = {2009}, month = {APR}, pages = {1092-1099}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Mn(1-x)Zn(x)Fe(2)O(4) nanoparticles (x = 0-1) were synthesized by wet chemical co-precipitation techniques. X-ray diffraction, transmission electron microscopy and high-resolution transmission electron microscopy were effectively utilized to investigate the different structural parameters. The elemental analysis was conducted using energy-dispersive spectrum and inductively coupled plasma analysis. The magnetic properties such as magnetization and coercivity were measured using vibrating sample magnetometer. The observed magnetization values of the nanoparticles were found to be lower compared to the bulk counterpart. The magnetization showed a gradual decrease with zinc substitution except for a small increase from x = 0.2 to 0.3. The Curie temperature was found to be enhanced in the case of ferrites in the nanoregime. The variation in lattice constant, reduced magnetization values, variation of magnetization with zinc substitution, the presence of a net magnetic moment for the zinc ferrite and the enhancement in Curie temperature in Mn(1-x)Zn(x)Fe(2)O(4) all provide evidence to the existence of a metastable cation distribution together with possible surface effects at the nanoregime. (C) 2008 Elsevier B.V. All rights reserved.

}, keywords = {Manganese zinc ferrite}, issn = {0304-8853}, doi = {10.1016/j.jmmm.2008.10.031}, author = {Gopalan, E. Veena and Al-Omari, I. A. and Malini, K. A. and Joy, Pattayil Alias and Kumar, D. Sakthi and Yoshida, Yasuhiko and Anantharaman, Maliemadom R.} } @article { ISI:000277203500017, title = {Template-assisted synthesis and characterization of passivated nickel nanoparticles}, journal = {Nanoscale Research Letters}, volume = {5}, number = {5}, year = {2010}, month = {MAY}, pages = {889-897}, publisher = {SPRINGER}, address = {233 SPRING ST, NEW YORK, NY 10013 USA}, abstract = {

Potential applications of nickel nanoparticles demand the synthesis of self-protected nickel nanoparticles by different synthesis techniques. A novel and simple technique for the synthesis of self-protected nickel nanoparticles is realized by the inter-matrix synthesis of nickel nanoparticles by cation exchange reduction in two types of resins. Two different polymer templates namely strongly acidic cation exchange resins and weakly acidic cation exchange resins provided with cation exchange sites which can anchor metal cations by the ion exchange process are used. The nickel ions which are held at the cation exchange sites by ion fixation can be subsequently reduced to metal nanoparticles by using sodium borohydride as the reducing agent. The composites are cycled repeating the loading reduction cycle involved in the synthesis procedure. X-Ray Diffraction, Scanning Electron Microscopy, Transmission Electron microscopy, Energy Dispersive Spectrum, and Inductively Coupled Plasma Analysis are effectively utilized to investigate the different structural characteristics of the nanocomposites. The hysteresis loop parameters namely saturation magnetization and coercivity are measured using Vibrating Sample Magnetometer. The thermomagnetization study is also conducted to evaluate the Curie temperature values of the composites. The effect of cycling on the structural and magnetic characteristics of the two composites are dealt in detail. A comparison between the different characteristics of the two nanocomposites is also provided.

}, keywords = {Nickel nanoparticles, Polymer-metal nanocomposites, Strongly acidic cation exchange resin, Stuctural and magnetic properties, Weakly acidic cation exchange resin}, issn = {1556-276X}, doi = {10.1007/s11671-010-9580-7}, author = {Gopalan, E. Veena and Malini, K. A. and Santhoshkumar, G. and Narayanan, T. N. and Joy, Pattayil Alias and Al-Omari, I. A. and Kumar, D. Sakthi and Yoshida, Yasuhiko and Anantharaman, Maliemadom R.} }