@article { ISI:000288092200005, title = {Preparation and characterization of bioceramic nanocomposites based on hydroxyapatite (HA) and carboxymethyl cellulose (CMC)}, journal = {Macromolecular Research}, volume = {18}, number = {12}, year = {2010}, month = {DEC}, pages = {1160-1167}, publisher = {SPRINGER}, address = {233 SPRING ST, NEW YORK, NY 10013 USA}, abstract = {

We report the synthesis of biomimetic nanocomposites based on carboxymethyl cellulose (CMC) and hydroxyapatite (HA) nanoparticles via a co-precipitation method. Physico-chemical characterization was performed before and after calcination by Fourier transform infrared (FTIR) spectroscopy, solid state (31)P nuclear magnetic resonance (NMR) spectroscopy, and thermogravimetric analysis (TGA). The formation of nanocomposites was observed by wide angle X-ray diffraction (WAXD), scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDX), and transmission electron microscopy (TEM). The spectral and crystallographic data indicated the formation of hydroxyapatite in the presence of CMC. They were observed as aggregates of HA nanoparticles and CMC, whose sizes were approximately similar to 260 +/- 40 nm. The crystallite size of the hydroxyapatite particles decreased (with 2 wt\% 18 +/- 3 nm) with increasing CMC content. The morphological aspects of the calcined samples revealed the sintering ability of HA nanoparticles. Nanocomposites of hydroxyapatite nanoparticles that mimic the process of nucleation and growth in nature can be prepared using biomacromolecules such as CMC.

}, keywords = {biopolymer, cellulose, hydroxyapatite, Nanoparticles, Particle size, X-ray diffraction}, issn = {1598-5032}, doi = {10.1007/s13233-010-1208-3}, author = {Kumar, Annamalai Pratheep and Mohaideen, Kamal Khaja and Alariqi, Sameh A. S. and Singh, Raj Pal} } @article { ISI:000281175500059, title = {Simple chemical co-precipitation/calcination route for the synthesis of simulated synroc-B and synroc-C powders}, journal = {Materials Chemistry and Physics}, volume = {123}, number = {2-3}, year = {2010}, month = {OCT}, pages = {695-699}, publisher = {ELSEVIER SCIENCE SA}, address = {PO BOX 564, 1001 LAUSANNE, SWITZERLAND}, abstract = {

A simple chemical co-precipitation/calcination route was developed for the synthesis of simulated synroc-B and synroc-C powders using mostly nitrate salts as starting chemicals and 20\% ammonia solution as precipitant. In this route, a mixed solution containing Al-nitrate, Ca-nitrate, Ba-nitrate, zirconyl nitrate and titanyl nitrate in the molar proportion required for synroc-B is added to dilute ammonia solution to precipitate these cations in the form of their hydroxides at room temperature by maintaining pH approximate to 10.5 during precipitation. Formation of a major fluorite phase with minor amounts of anatase, rutile and hollandite phases is observed in the powder obtained after calcination in air at 750 degrees C. Multiphase crystalline synroc-B matrix containing hollandite, perovskite, zirconolite, and rutile phases is obtained after sintering the heat treated powder in the form of pellets at 1230 degrees C for 4h in air. Similarly, pure synroc-C phases with 14 and 20\% simulated waste loadings were synthesized following the same synthesis protocol. These pre-treated powders with a high surface area of similar to 25 m(2) g(-1) gave sintered ceramics having density of similar to 90\% for 14 and 20\% waste loadings. (C) 2010 Elsevier B.V. All rights reserved.

}, keywords = {Ceramics, Chemical synthesis, Oxides, Sintering}, issn = {0254-0584}, doi = {10.1016/j.matchemphys.2010.05.039}, author = {Potdar, H. S. and Vijayanand, S. and Mohaideen, Kamal Khaja and Patil, K. R. and Joy, Pattayil Alias and Madhavan, R. Raja and Kutty, K. V. G. and Ambashta, Ritu D. and Wattal, P. K.} } @article { ISI:000313149800004, title = {Enhancement in the magnetostriction of sintered cobalt ferrite by making self-composites from nanocrystalline and bulk powders}, journal = {ACS Applied Materials \& Interfaces}, volume = {4}, number = {12}, year = {2012}, month = {DEC}, pages = {6421-6425}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Sintered polycrystalline cobalt ferrite is a potential magnetostrictive smart material for applications as sensors and actuators. A novel concept of enhancing the magnetostrictive strain of sintered cobalt ferrite by making self-composites from nanosized and bulk powders with different particle sizes of the same material as components is reported. The self-composites give higher magnetostriction coefficient and strain derivative when compared to the sintered products obtained from the individual powders. The individual components give a maximum magnetostriction up to similar to 310 ppm, whereas up to similar to 370 ppm is obtained for a two-component system consisting of powders of two different sizes. On the other hand, a three-component self-composite made from starting powders of 3 nm, 40 nm and \>1 mu m give very high magnetostriction of similar to 400 ppm at 800 kA/m, suitable for making devices.

}, keywords = {Cobalt ferrite, Magnetostriction, Nanocrystalline, self-composite, Sintering}, issn = {1944-8244}, doi = {10.1021/am302053q}, author = {Mohaideen, Kamal Khaja and Joy, Pattayil Alias} } @article { ISI:000308263100040, title = {High magnetostriction and coupling coefficient for sintered cobalt ferrite derived from superparamagnetic nanoparticles}, journal = {Applied Physics Letters}, volume = {101}, number = {7}, year = {2012}, month = {AUG}, pages = {072405}, publisher = {AMER INST PHYSICS}, address = {CIRCULATION \& FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA}, abstract = {

High magnetostriction (lambda) and coupling coefficient (d lambda/dH) of 315 ppm and 1.97 x 10(-9) A(-1) m, respectively, are obtained at room temperature for sintered cobalt ferrite derived from nanocrystalline powders. Also, the powder was compacted at a low pressure of 8 MPa and sintered for a short duration of 10 min at 1450 degrees C. Magnetic annealing at 300 degrees C in a field of 0.5 T for 30 min further enhanced the magnetostriction coefficient to 345 ppm with a higher coupling coefficient 2.12 x 10(-9) A(-1)m. The magnetic field above which maximum magnetostriction is observed is reduced by almost half after magnetic annealing. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4745922]

}, issn = {0003-6951}, doi = {10.1063/1.4745922}, author = {Mohaideen, Kamal Khaja and Joy, Pattayil Alias} } @article { ISI:000324099300024, title = {High magnetostriction coefficient of Mn substituted cobalt ferrite sintered from nanocrystalline powders and after magnetic field annealing}, journal = {Current Applied Physics}, volume = {13}, number = {8}, year = {2013}, month = {OCT}, pages = {1697-1701}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Magnetostriction characteristics of Mn substituted cobalt ferrite, CoFe2-xMnxO4 (0 \<= x \<= 0.3), sintered from nanocrystalline powders of average particle size of similar to 4 nm have been studied. Larger value of magnetostriction at lower magnetic field is achieved after substitution of Mn for Fe. The maximum value of magnetostriction coefficient is not much affected and the slope of the magnetostriction is increased with increasing Mn content. Higher maximum value of magnetostriction coefficient (lambda) of 234 ppm comparable to that of the unsubstituted composition with larger strain derivative (d lambda/dH) is obtained for x = 0.2 in CoFe2-xMnxO4. The magnetostriction coefficient is increased to 262 ppm with further enhancement in the strain derivative after annealing the sintered compact at 300 degrees C in a magnetic field of 400 kA/m for 30 min. (C) 2013 Elsevier B.V. All rights reserved.

}, keywords = {Cobalt ferrite, Magnetic field annealing, Magnetostriction, Mn substitution, Nanocrystalline}, issn = {1567-1739}, doi = {10.1016/j.cap.2013.06.030}, author = {Mohaideen, Kamal Khaja and Joy, Pattayil Alias} } @article { ISI:000324311200017, title = {Influence of initial particle size on the magnetostriction of sintered cobalt ferrite derived from nanocrystalline powders}, journal = {Journal of Magnetism and Magnetic Materials}, volume = {346}, year = {2013}, month = {NOV}, pages = {96-102}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

The role of initial particle size on the magnetostriction coefficient of sintered cobalt ferrite derived from nanocrystalline powders is studied. Nanoparticles of cobalt ferrite with different sizes in the range 3-80 nm are synthesized by an autocombustion method using metal nitrates and glycine. It has been observed that the initial particle size of the starting powders has a strong influence on the magnetostrictive behavior of sintered cobalt ferrite. Highest magnetostrictive strain and strain derivative are obtained for sintered ferrite derived from nanoparticles of size \< 5 nm. The results show that higher magnetostriction coefficient for sintered cobalt ferrite can be achieved by compacting nanocrystalline particles of very small size. (C) 2013 Elsevier B.V. All rights reserved.

}, keywords = {Cobalt ferrite, magnetic properties, Magnetostriction, Microstructure, Nanocrystalline, Particle size}, issn = {0304-8853}, doi = {10.1016/j.jmmm.2013.07.016}, author = {Mohaideen, Kamal Khaja and Joy, Pattayil Alias} } @article { ISI:000341165000020, title = {High magnetostriction parameters for low-temperature sintered cobalt ferrite obtained by two-stage sintering}, journal = {Journal of Magnetism and Magnetic Materials}, volume = {371}, year = {2014}, month = {DEC}, pages = {121-129}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

From the studies on the magnetostriction characteristics of two-stage sintered polycrystalline CoFe2O4 made from nanocrystalline powders, it is found that two-stage sintering at low temperatures is very effective for enhancing the density and for attaining higher magnetostriction coefficient. Magnetostriction coefficient and strain derivative are further enhanced by magnetic field annealing and relatively larger enhancement in the magnetostriction parameters is obtained for the samples sintered at lower temperatures, after magnetic annealing, despite the fact that samples sintered at higher temperatures show larger magnetostriction coefficients before annealing. A high magnetostriction coefficient of similar to 380 ppm is obtained after field annealing for the sample sintered at 1100 degrees C, below a magnetic field of 400 kA/m, which is the highest value so far reported at low magnetic fields for sintered polycrystalline cobalt ferrite. (C) 2014 Elsevier B.V. All rights reserved.

}, keywords = {Cobalt ferrite, Magnetostriction, Two-stage sintering}, issn = {0304-8853}, doi = {10.1016/j.jmmm.2014.07.013}, author = {Mohaideen, Kamal Khaja and Joy, Pattayil Alias} } @article { ISI:000329554400013, title = {Studies on the effect of sintering conditions on the magnetostriction characteristics of cobalt ferrite derived from nanocrystalline powders}, journal = {Journal of the European Ceramic Society}, volume = {34}, number = {3}, year = {2014}, month = {MAR}, pages = {677-686}, publisher = {ELSEVIER SCI LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {

The effect of sintering conditions on the magnetostriction characteristics of sintered cobalt ferrite derived from nanocrystalline powders is studied. It is observed that the magnetostriction coefficient as well as the slope of the magnetostriction as a function of field depends on the microstructure of the sintered product. There is a direct correlation between the magnetostriction characteristics and density as well as porosity of the sintered products. Intragranular pores are found to be strongly influencing the magnetostriction characteristics. Similarly, correlation is found between the magnetostriction parameters and the Curie temperature, indicating the role of cation distribution which affects the magnetic anisotropy. Sintering the compacts made from nanocrystalline powders at 1450 degrees C for a very short duration is found to give high values of magnetostriction coefficient. However, higher values of magnetostriction at low magnetic fields are obtained for samples sintered at lower temperatures for longer duration and having relatively lower density. (C) 2013 Elsevier Ltd. All rights reserved.

}, keywords = {Cobalt ferrite, Magnetostriction, Microstructure, Nanocrystalline, Sintering}, issn = {0955-2219}, doi = {10.1016/j.jeurceramsoc.2013.09.018}, author = {Mohaideen, Kamal Khaja and Joy, Pattayil Alias} }