02118nas a2200217   4500008004100000022001400041245009100055210006900146260008000215300001400295490000700309520130500316100001901621700002201640700001901662700002501681700001801706700002201724700003301746856012101779       2006                        eng d  a0957-448400aEvidence for intergranular tunnelling in polyaniline passivated alpha-Fe nanoparticles0 aEvidence for intergranular tunnelling in polyaniline passivated   aDIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLANDbIOP PUBLISHING LTDcSEP  a4765-47720 v173 a<p>Nanoparticles are of immense importance both from the fundamental and application points of view. They exhibit quantum size effects which are manifested in their improved magnetic and electric properties. Mechanical attrition by high energy ball milling (HEBM) is a top down process for producing fine particles. However, fineness is associated with high surface area and hence is prone to oxidation which has a detrimental effect on the useful properties of these materials. Passivation of nanoparticles is known to inhibit surface oxidation. At the same time, coating polymer film on inorganic materials modifies the surface properties drastically. In this work a modified set-up consisting of an RF plasma polymerization technique is employed to coat a thin layer of a polymer film on Fe nanoparticles produced by HEBM. Ball-milled particles having different particle size ranges are coated with polyaniline. Their electrical properties are investigated by measuring the dc conductivity in the temperature range 10-300 K. The low temperature dc conductivity (I-V) exhibited nonlinearity. This nonlinearity observed is explained on the basis of the critical path model. There is clear-cut evidence for the occurrence of intergranular tunnelling. The results are presented here in this paper.</p>1 aSunny, Vijutha1 aNarayanan, T., N.1 aSajeev, U., S.1 aJoy, Pattayil, Alias1 aKumar, Sakthi1 aYoshida, Yasuhiko1 aAnantharaman, Maliemadom, R.  uhttps://library.ncl.res.in/content/evidence-intergranular-tunnelling-polyaniline-passivated-alpha-fe-nanoparticles-001783nas a2200265   4500008004100000022001400041245007000055210006900125260006900194300001200263490000800275520088300283653002401166653002501190653002501215653002301240653001901263653001901282100001901301700001901320700001601339700002501355700003301380856010401413       2010                        eng d  a0925-838800aFlexible microwave absorber based on nickel ferrite nanocomposite0 aFlexible microwave absorber based on nickel ferrite nanocomposit  aPO BOX 564, 1001 LAUSANNE, SWITZERLANDbELSEVIER SCIENCE SAcJAN  a297-3030 v4893 a<p>Flexible magnetic composite materials were prepared by incorporating precharacterized nickel ferrite nanoparticles in a natural rubber matrix. The complex dielectric permittivity and magnetic permeability of the composites were measured at different microwave frequencies using the cavity perturbation technique. A steady increase in dielectric permittivity was observed with increase in filler concentration. Maxwell-Garnett mixture equations were employed to model the effective permittivity and permeability of the composite. Reflection loss was estimated by employing the model of single layer absorber backed with a perfect conductor. Reflection loss minima of -5.9 dB at 3.2 GHz for 12 mm thick rubber ferrite composite sheet is obtained in the S-band while a loss up to -16 dB could be achieved at 9.5 GHz in the X-band. (C) 2009 Elsevier B.V. All rights reserved.</p>10aCavity perturbation10aComplex permeability10aComplex permittivity10aMicrowave absorber10aNanocomposites10aNickel ferrite1 aSunny, Vijutha1 aKurian, Philip1 aMohanan, P.1 aJoy, Pattayil, Alias1 aAnantharaman, Maliemadom, R.  uhttps://library.ncl.res.in/content/flexible-microwave-absorber-based-nickel-ferrite-nanocomposite-002114nas a2200277   4500008004100000022001400041245013400055210006900189260005700258300001400315490000600329520109600335653002101431653002601452653002401478653001501502653002301517100002701540700002201567700001901589700002001608700002201628700002501650700003301675856012801708       2010                        eng d  a1931-757300aSynthesis of bio-compatible SPION-based aqueous ferrofluids and evaluation of radiofrequency power loss for magnetic hyperthermia0 aSynthesis of biocompatible SPIONbased aqueous ferrofluids and ev  a233 SPRING ST, NEW YORK, NY 10013 USAbSPRINGERcOCT  a1706-17110 v53 a<p>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.</p>10aMagnetic heating10aMagnetic hyperthermia10aMagnetic relaxation10aPower loss10aSuperparamagnetism1 aMary, Antony, P. Reena1 aNarayanan, T., N.1 aSunny, Vijutha1 aSakthikumar, D.1 aYoshida, Yasuhiko1 aJoy, Pattayil, Alias1 aAnantharaman, Maliemadom, R.  uhttps://library.ncl.res.in/content/synthesis-bio-compatible-spion-based-aqueous-ferrofluids-and-evaluation-radiofrequency-001908nas a2200217   4500008004100000022001400041245012100055210006900176260012500245300001100370490000800381520101800389100001901407700002001426700001901446700001601465700001901481700002501500700003301525856013201558       2014                        eng d  a0021-897900aFlexible microwave absorbers based on barium hexaferrite, carbon black, and nitrile rubber for 2-12 GHz applications0 aFlexible microwave absorbers based on barium hexaferrite carbon   aCIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USAbAMER INST PHYSICScJUL  a0249020 v1163 a<p>Flexile single layer electromagnetic wave absorbers were designed by incorporating appropriate amounts of carbon black in a nitrile butadiene rubber matrix along with an optimized amount of magnetic counterpart, namely, barium hexaferrite for applications in S, C, and X-bands. Effective dielectric permittivity and magnetic permeability were measured using cavity perturbation method in the frequency range of 2-12 GHz. The microwave absorbing characteristics of the composites were studied in the S, C, and X-bands employing a model in which an electromagnetic wave is incident normally on a metal terminated single layer. Reflection loss exceeding -20 dB is obtained for all the samples in a wide frequency range of 2-12 GHz when an appropriate absorber thickness between 5 and 9 mm is chosen. The impact of carbon black is clearly observed in the optimized composites on the mechanical strength, thickness, band width of absorption, dielectric properties, and absorptivity. (C) 2014 AIP Publishing LLC.</p>1 aVinayasree, S.1 aSoloman, M., A.1 aSunny, Vijutha1 aMohanan, P.1 aKurian, Philip1 aJoy, Pattayil, Alias1 aAnantharaman, Maliemadom, R.  uhttps://library.ncl.res.in/content/flexible-microwave-absorbers-based-barium-hexaferrite-carbon-black-and-nitrile-rubber-2-12-0