@article { ISI:000236477800029, title = {Size-dependent magnetic properties of nanocrystalline yttrium iron garnet powders}, journal = {Journal of Magnetism and Magnetic Materials}, volume = {301}, number = {1}, year = {2006}, month = {JUN}, pages = {212-219}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Yttrium iron garnet (YIG) powders with particle sizes of 9, 14, 25 and 60 nm have been synthesised and their magnetic properties have been studied as a function of particle size and temperature. The particles with sizes of 9 and 14 nm exhibited superparamagnetism. The blocking temperature (T-B) decreased with decreasing particle size, whereas the anisotropy constant (K) increased. The saturation magnetisation (M-s) decreased with decreasing particle size. These variations are attributed to large surface-to-volume ratios in nanoparticles where the surface moments are predominant. (c) 2005 Published by Elsevier B.V.

}, keywords = {anisotropy constant, Magnetism, Nanoparticles, Superparamagnetism, YIG}, issn = {0304-8853}, doi = {10.1016/j.jmmm.2005.06.027}, author = {Rajendran, M. and Deka, Sasanka and Joy, Pattayil Alias and Bhattacharya, Asish K.} } @article { ISI:000260776800023, title = {Superparamagnetic nanocrystalline ZnFe2O4 with a very high curie temperature}, journal = {Journal of Nanoscience and Nanotechnology}, volume = {8}, number = {8}, year = {2008}, month = {AUG}, pages = {3955-3958}, publisher = {AMER SCIENTIFIC PUBLISHERS}, address = {25650 NORTH LEWIS WAY, STEVENSON RANCH, CA 91381-1439 USA}, abstract = {

Studies on the magnetic properties of nanocrystalline ZnFe2O4 synthesized by an autocombustion method are reported. Superparamagnetic behavior is observed for the nanocrystalline materials with particle sizes of 8 nm and 17 nm, with superparamagnetic blocking temperatures of 65 K and 75 K, respectively. Magnetic hysteresis with very large coercivities of 533 Oe and 325 Oe, respectively, are observed at 12 K. Studies on the temperature variation of the magnetization above room temperature indicate that the Curie temperature is as high as similar to 800 K when compared to the paramagnetic nature of bulk zinc ferrite at room temperature.

}, keywords = {Curie temperature, Nanocrystalline, Superparamagnetism, Zinc Ferrite}, issn = {1533-4880}, doi = {10.1166/jnn.2008.201}, author = {Deka, Sasanka and Joy, Pattayil Alias} } @article { ISI:000208013800005, title = {Superparamagnetic nanocomposite of magnetite and activated carbon for removal of dyes from waste water}, journal = {Nanoscience and Nanotechnology Letters}, volume = {1}, number = {3}, year = {2009}, month = {DEC}, pages = {171-175}, publisher = {AMER SCIENTIFIC PUBLISHERS}, address = {25650 NORTH LEWIS WAY, STEVENSON RANCH, CA 91381-1439 USA}, abstract = {

Nanocomposite of superparamagnetic Fe(3)O(4) and activated carbon (AC) is synthesized at room temperature and characterized by various techniques. Magnetic measurements indicated that the Fe(3)O(4) nanoparticles are isolated by the AC particles. The magnetic fluid obtained by dispersion of the nanocomposite in water is found to be relatively stable. The dispersion is found to be very efficient for the removal of methylene blue dye from water. Thus, the nanocomposite is highly suitable for removing dissolved dyes and other contaminants from waste water by a simple magnetic separation process after adsorption on AC.

}, keywords = {Magnetic Separation, Nanocomposite, Superparamagnetism, Water Purification}, issn = {1941-4900}, doi = {10.1166/nnl.2009.1031}, author = {Thakuria, Pankaj and Joy, Pattayil Alias} } @article { ISI:000283124800028, title = {Synthesis of bio-compatible SPION-based aqueous ferrofluids and evaluation of radiofrequency power loss for magnetic hyperthermia}, journal = {Nanoscale Research Letters}, volume = {5}, number = {10}, year = {2010}, month = {OCT}, pages = {1706-1711}, publisher = {SPRINGER}, address = {233 SPRING ST, NEW YORK, NY 10013 USA}, abstract = {

Bio-compatible magnetic fluids having high saturation magnetization find immense applications in various biomedical fields. Aqueous ferrofluids of superparamagnetic iron oxide nanoparticles with narrow size distribution, high shelf life and good stability is realized by controlled chemical co-precipitation process. The crystal structure is verified by X-ray diffraction technique. Particle sizes are evaluated by employing Transmission electron microscopy. Room temperature and low-temperature magnetic measurements were carried out with Superconducting Quantum Interference Device. The fluid exhibits good magnetic response even at very high dilution (6.28 mg/cc). This is an advantage for biomedical applications, since only a small amount of iron is to be metabolised by body organs. Magnetic field induced transmission measurements carried out at photon energy of diode laser (670 nm) exhibited excellent linear dichroism. Based on the structural and magnetic measurements, the power loss for the magnetic nanoparticles under study is evaluated over a range of radiofrequencies.

}, keywords = {Magnetic heating, Magnetic hyperthermia, Magnetic relaxation, Power loss, Superparamagnetism}, issn = {1931-7573}, doi = {10.1007/s11671-010-9729-4}, author = {Mary, Antony P. Reena and Narayanan, T. N. and Sunny, Vijutha and Sakthikumar, D. and Yoshida, Yasuhiko and Joy, Pattayil Alias and Anantharaman, Maliemadom R.} }