@article { ISI:000241306000020, title = {Characterization of nanosized NiZn ferrite powders synthesized by an autocombustion method}, journal = {Materials Chemistry and Physics}, volume = {100}, number = {1}, year = {2006}, month = {NOV}, pages = {98-101}, publisher = {ELSEVIER SCIENCE SA}, type = {Article}, address = {PO BOX 564, 1001 LAUSANNE, SWITZERLAND}, abstract = {

Nanocrystalline Ni0.5Zn0.5Fe2O4 with average particle size of similar to 9 nm has been synthesized by an autocombustion method and characterized by powder XRD, TEM and room temperature magnetic measurements. High room temperature magnetization comparable to that of the bulk material is obtained for the nanosized powders annealed at 800 degrees C, with a maximum particle size of similar to 54 nm. The results show that optimum properties can be achieved for NiZn ferrite powders synthesized by the present autocombustion method and processed at relatively lower temperatures. (c) 2005 Elsevier B.V. All rights reserved.

}, keywords = {Chemical synthesis, Magnetic materials, magnetic properties, Oxides}, issn = {0254-0584}, doi = {10.1016/j.matchemphys.2005.12.012}, author = {Deka, Sasanka and Joy, Pattayil Alias} } @article { ISI:000236784200028, title = {Finite size effects on the structural and magnetic properties of sol-gel synthesized NiFe2O4 powders}, journal = {Journal of Magnetism and Magnetic Materials}, volume = {302}, number = {1}, year = {2006}, month = {JUL}, pages = {190-195}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Nanoparticles of nickel ferrite have been synthesized by the sol-gel method and the effect of grain size oil its structural and magnetic properties have been Studied in detail. X-ray diffraction (XRD) studies revealed that all the samples are single phasic possessing the inverse spinel structure. Grain size of the sol-gel synthesized powders has been determined from the XRD data and the strain graph. A grain size of 9 nm was observed for the as prepared powders of NiFe2O4 obtained through the sol-gel method. It was also observed that strain was induced during the firing process. Magnetization measurements have been carried out on all the samples prepared in the present series. It was found that the specific magnetization of the nanosized NiFe2O4 powders was lower than that of the corresponding coarse-grained counterparts and decreased with a decrease in grain size. The coercivity of the sol-gel synthesized NiFe2O4 nanoparticles attained a maximum value when the grain size was 15 nm and then decreased as the grain size was increased further. (c) 2005 Elsevier B.V. All rights reserved.

}, keywords = {grain size, magnetic properties, Nanoparticles, Nickel ferrite, strain}, issn = {0304-8853}, doi = {10.1016/j.jmmm.2005.08.029}, author = {George, M. and John, A. M. and Nair, S. S. and Joy, Pattayil Alias and Anantharaman, Maliemadom R.} } @article { ISI:000241949000010, title = {Role of ligands in the formation, phase stabilization, structural and magnetic properties of alpha-Fe2O3 nanoparticles}, journal = {Journal of Nanoparticle Research}, volume = {8}, number = {5}, year = {2006}, month = {OCT}, pages = {635-643}, publisher = {SPRINGER}, type = {Article}, address = {VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS}, abstract = {

The electrochemical synthesis of alpha Fe2O3 nanoparticles was performed using quaternary ammonium salts viz. TPAB, TBAB and TOAB in an organic medium by optimizing current density and molar concentration of the ligand. The role of ligands in the formation of alpha phase, structure and magnetic properties was investigated in details. The effect of increasing chain length on the particle size confirmed that as the chain length increases from propyl to octyl, the particle size decreases. X-ray diffraction spectra of as prepared samples and TEM analysis confirmed the amorphous nature of iron oxide. TEM showed beads of iron oxide joined together with a size distribution in the range of 6-30 nm. The Mossbauer studies also support this observation that for the lowest particle size, the line width is broader which successively reduces with increase in particle size. Iron oxide capped with TOAB indicated superparamagnetic nature at room temperature. The resultant internal magnetic field of 506 mm/s due to hyperfine splitting clearly established the formation of alpha-Fe2O3 The infrared spectroscopy and pH measurements revealed the binding of tetra alkyl ligand with iron oxide. The IR spectra and the increase in basicity of as prepared samples confirmed the formation of hydrated iron oxide. Above 800 degrees C the spectra indicated only iron oxide. Surface area obtained by BET method was 205 m(2)/g.

}, keywords = {Alkyl chain length, alpha-Fe2O3, Electrochemistry, magnetic properties, Nanoparticles, narrow size distribution}, issn = {1388-0764}, doi = {10.1007/s11051-005-9033-x}, author = {Joshi, Satyawati S. and Patil, Prajakta R. and Nimase, Madhav S. and Bakare, P. P.} } @article { ISI:000244006000001, title = {Direct comparison of the aging and memory effects of magnetic nanoclusters and nanoparticles}, journal = {Solid State Communications}, volume = {141}, number = {6}, year = {2007}, month = {FEB}, pages = {307-310}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

The magnetic characteristics of a dense magnetic nanoparticle system and a spin glass system consisting of magnetic nanoclusters are compared. Zero field cooled and field cooled magnetization measurements, including aging and memory experiments, of the nanoparticle and the magnetic cluster systems show similar characteristics, suggesting a common origin for the spin glass-type behavior of the magnetic nanoparticle and nanocluster systems. (C) 2006 Published by Elsevier Ltd.

}, keywords = {Magnetic nanoparticles, magnetic properties, spin glasses}, issn = {0038-1098}, doi = {10.1016/j.ssc.2006.11.015}, author = {Sankar, C. Raj and Vijayanand, S. and Verma, Seema and Joy, Pattayil Alias} } @article {Mueller, title = {Reactions of o-aminothiophenol and o-aminophenyl disulfide with itaconic anhydride and (-)-dimenthyl itaconate: access to enantiomerically pure 1,5-benzothiazepines and benzothiazolyl-2-methylacrylic acid}, journal = {Synthesis-Stuttgart}, number = {3}, year = {2007}, month = {FEB}, pages = {457-463}, publisher = {GEORG THIEME VERLAG KG}, type = {Article}, address = {RUDIGERSTR 14, D-70469 STUTTGART, GERMANY}, abstract = {

{A facile chemo- and regioselective reactions of o-aminothiophenol (o-ATP) with itaconic anhydride is described. 1,5-Benzothiazepinyl-3-acetic acid is obtained in 81\% yield via the exclusive Michael type addition of the thiol unit from o-ATP to the carbon-carbon double bond in itaconic anhydride followed by an intramolecular anhydride ring opening with an amine unit. The moderately stereoselective Michael type addition of the thiol unit from o-ATP to (-)-dimenthyl itaconate to obtain a mixture of diastereomers in a 7:3 ratio in 82\% yield has been demonstrated. The reductive sulfur-sulfur bond cleavage in the dicarboxylic acid, 2({2-[2-(3-carboxybut-3-enoylamino)phenyidisulfanyl]phenylcarbamoyl\

}, keywords = {Magnetic nanoparticles, magnetic properties, spin glasses}, issn = {0936-5214}, doi = {10.1055/s-2006-958977}, author = {Baag, Md. Merajuddin and Sahoo, Manoj Kumar and Puranik, Vedavati G. and N. P. Argade} } @article { ISI:000246042800003, title = {Synthesis and magnetic properties of Mn doped ZnO nanowires}, journal = {Solid State Communications}, volume = {142}, number = {4}, year = {2007}, month = {APR}, pages = {190-194}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

Mn doped ZnO nanowires have been synthesized using a simple autocombustion method. The as-synthesized Mn doped ZnO nanowires were characterized by X-ray diffraction and transmission electron microscopy. An increase in the hexagonal lattice parameters of ZnO is observed on increasing the Mn concentration. Optical absorption studies show an increment in the band gap with increasing Mn content, and also give evidence for the presence of Mn2+ ions in tetrahedral sites. All Zn1-xMnxO (0 \<= x \<= 0.25) samples are paramagnetic at room temperature. However, a large increase in the magnetization is observed below 50 K. This behavior, along with the negative value of the Weiss constant obtained from the linear fit to the susceptibility data below room temperature, indicate ferrimagnetic behavior. The origin of ferrimagnetism is likely to be either the intrinsic characteristics of the Mn doped samples, or due to some spinel-type impurity phases present in the samples that could not be detected. (c) 2007 Elsevier Ltd. All rights reserved.

}, keywords = {Combustion synthesis, diluted magnetic semiconductor, magnetic properties, Mn doped ZnO}, issn = {0038-1098}, doi = {10.1016/j.ssc.2007.02.017}, author = {Deka, Sasanka and Joy, Pattayil Alias} } @article { ISI:000261361900032, title = {Low temperature synthesis of nanocrystalline lithium ferrite by a modified citrate gel precursor method}, journal = {Materials Research Bulletin}, volume = {43}, number = {12}, year = {2008}, month = {DEC}, pages = {3447-3456}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

Single phase nanocrystalline lithium ferrite is synthesized by a modified citrate gel precursor technique. Ferrite nanoparticles of average size of 8 nm, obtained after calcination of the citrate gel Made by the usual method at 450 degrees C, show superparamagnetic behavior. However, small amounts of alpha-Fe(2)O(3) is formed as an impurity phase clue to the initial formation of some gamma-Fe(2)O(3) phase. Oil the other hand, when the pH of the mixed Solution is increased to 7 after the addition of ammonia Solution, a lower calcination temperature of 200 degrees C is sufficient for the formation of single phase lithium ferrite nanoparticles of size 30 nm. No impurity phases are detected when the nanocrystalline powders arc calcined at higher temperatures. The magnetic properties of the ferrite nanoparticles of different sizes obtained by calcining the powders at different temperatures are studied. (C) 2008 Elsevier Ltd. All rights reserved.

}, keywords = {Chemical synthesis, Magnetic materials, magnetic properties, Nanostructures, Oxides}, issn = {0025-5408}, doi = {10.1016/j.materresbull.2008.01.023}, author = {Verma, Seema and Joy, Pattayil Alias} } @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:000255342500023, title = {Temperature dependent structural studies and magnetic properties of BaCa2Fe16O27 hexaferrites prepared by stearic acid gel route in presence of SDS surfactant}, journal = {Synthesis and Reactivity in Inorganic Metal-Organic and Nano-Metal Chemistry}, volume = {38}, number = {2}, year = {2008}, note = {Symposium on New Routes to Inorganic Materials, Films and Nanocrystals held at ICMAT 2007, Singapore, SINGAPORE, JUL 01-06, 2007}, month = {MAR}, pages = {225-228}, publisher = {TAYLOR \& FRANCIS INC}, type = {Article, Proceedings Paper}, address = {325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA}, abstract = {

The preparation of BaCa2Fe16O27 hexaferrite powders by a stearic acid gel method with SDS surfactant has been investigated at various sintering temperatures. The samples were characterized by X-ray diffraction, scanning electron microscopy (SEM), TGA, FTIR and vibrating sample magnetometer (VSM). The effect of sintering temperature on properties of BaCa2Fe16O27 hexaferrites was studied. In presence of sodium dodecyl sulfate (SDS) surfactant, the magnetic parameters, like saturation magnetization, coercivity and remanent magnetization, have been calculated from hysteresis loop.

}, keywords = {BaCa2Fe16O27, magnetic properties, stearic acid gel method}, issn = {1553-3174}, doi = {10.1080/15533170801926549}, author = {Joyania, R. B. and Khomane, Ramdas B. and Chauhan, C. C. and Kulkarni, B. D.} } @article { ISI:000261555200036, title = {Valence-state analysis through spectroelectrochemistry in a series of quinonoid-bridged diruthenium complexes [(acac)(2)Ru(mu-L)Ru(acac)(2)](n) (n =+2,+1, 0,-1,-2)}, journal = {Chemistry-A European Journal}, volume = {14}, number = {34}, year = {2008}, month = {OCT}, pages = {10816-10828}, publisher = {WILEY-BLACKWELL}, type = {Article}, address = {COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA}, abstract = {

The quinonoid ligand-bridged diruthenium compounds [(acac)(2)Ru(mu-L2-)Ru(acac)(2)] (acac(-) = acetylacetonato = 2,4-pentanedionato; L2- = 2,5-dioxido-1,4-benzoquinone, 1; 3,6-dichloro-2,5-dioxido-1,4-benzoquinone, 2; 5,8-dioxido-1,4-naphthoquinone, 3; 2-3-dichloro-5,8-dioxido-1,4-naphthoquinone, 4; 1,5-dioxido-9,10-anthraquinone, 5; and 1,5-diimido-9,10-anthraquinone, 6) were prepared and characterized analytically. The crystal structure analysis of 5 in the rac configuration reveals two tris(2,4-pentanedionato)ruthenium moieties with an extended anthracenedione-derived bis(ketoenolatee) pi-conjugated bridging ligand. The weakly antiferro-magnetically coupled {Ru-III(mu-L2-)Ru{\textendash}(III)} configuration in 1-6 exhibits complicated overall magnetic and EPR responses,. ne simultaneous presence of highly redox-active quinonoid-bridging ligands and of two ruthenium centers capable of adopting the oxidation states +2, +3, and +4 creates a large variety of possible oxidation state combinations. Accordingly. the complexes 1-6 exhibit two reversible one-electron oxidation steps and at least two reversible reduction processes. Shifts to positive potentials were observed on introduction of Cl substituents (1 -\> 2, 3 -\> 4) or through replacement of NH by O (6 -\> 5). The ligand-to-metal charge transfer (LMCT) absorptions in the visible region of the neutral molecules become more intense and shifted to lower energies on stepwise reduction with two electrons. On oxidation, the para-substituted systems 1-4 exhibit monocation intermediates with intervalence charge transfer (IVCT) transitions of (RuRuIV)-Ru-III mixed-valent species. In contrast, the differently substituted systems 5 and 6 show no such near infrared (NIR) absorption. While the first reduction steps are thus assigned to largely ligand-centered processes, the oxidation appears to involve metal-ligand delocalized molecular orbitals with variable degrees of mixing.

}, keywords = {magnetic properties, quinones, ruthenium, spectroelectrochemistry, structure elucidation, valence-state distributions}, issn = {0947-6539}, doi = {10.1002/chem.200800976}, author = {Ghumaan, Sandeep and Sarkar, Biprajit and Maji, Somnath and Puranik, Vedavati G. and Fiedler, Jan and Urbanos, Francisco A. and Jimenez-Aparicio, Reyes and Kaim, Wolfgang and Lahiri, Goutam Kumar} } @article { ISI:000271843400019, title = {Ferromagnetic properties of glucose coated Cu2O nanoparticles}, journal = {Solid State Communications}, volume = {149}, number = {47-48}, year = {2009}, month = {DEC}, pages = {2199-2201}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

Magnetic properties of glucose coated cuprous oxide nanoparticles of different sizes have been studied. Unlike bulk Cu2O, which shows diamagnetic behavior, the nanoparticles show superparamagnetic behavior. A superparamagnetic blocking temperature of 21 K is observed for 5 nm particles. A magnetic hysteresis loop with a coercivity of 406 Oe is observed for these particles at 5 K. The magnetization and the coercivity increase with decreasing particle size. The superparamagnetic behavior, along with the increase in magnetization and coercivity with decreasing particle size, is due to the enhanced surface contributions to the magnetism. (C) 2009 Elsevier Ltd. All rights reserved.

}, keywords = {Chemical synthesis, Cuprous oxide, magnetic properties, Nanoparticles}, issn = {0038-1098}, doi = {10.1016/j.ssc.2009.09.013}, author = {Mahajan, Mangesh B. and Pavan, M. S. and Joy, Pattayil Alias} } @article { ISI:000207804200008, title = {Single step synthesis and properties of M/MFe2O4 and PVDF/M/MFe2O4 (M = Co, Ni) magnetic nanocomposites}, journal = {Science of Advanced Materials}, volume = {1}, number = {3}, year = {2009}, month = {DEC}, pages = {262-268}, publisher = {AMER SCIENTIFIC PUBLISHERS}, address = {26650 THE OLD RD, STE 208, VALENCIA, CA 91381-0751 USA}, abstract = {

Metal/ferrite nanocomposites (M/MFe2O4; M = Co, Ni), consisting of nanoparticles of a metal and the corresponding metal ferrite, have been synthesized under in situ conditions by a simple and single step process. The metal/ferrite nanocomposites embedded in a polymer matrix have been prepared by a simple hot-pressing method. The performance parameters such as magnetization, coercivity, permeability and dielectric constant of the two- and three-phase nanocomposite systems are compared. The coercivity increases and the permeability decreases with increasing polymer content in the three-phase composite. Enhancement of the dielectric constant is observed at low frequencies.

}, keywords = {Dielectric, Ferrite, magnetic properties, Nanocomposite, Nanocrystalline, permeability}, issn = {1947-2935}, doi = {10.1166/sam.2009.1053}, author = {Deka, Sasanka and Joy, Pattayil Alias and Kumar, A. Pratheep} } @article { ISI:000276938100029, title = {On the magnetic and dielectric properties of nickel-neoprene nanoconaposites}, journal = {Materials Chemistry and Physics}, volume = {121}, number = {1-2}, year = {2010}, month = {MAY}, pages = {154-160}, publisher = {ELSEVIER SCIENCE SA}, address = {PO BOX 564, 1001 LAUSANNE, SWITZERLAND}, abstract = {

Nickel nanocomposites were prepared by incorporating nickel nanoparticles in a neoprene matrix according to a specific recipe for various loadings of nickel particles. The dielectric properties of these composites were evaluated for different frequencies ranging from 100 kHz to 8 MHz at different temperatures from 30 degrees C to 120 degrees C. The dielectric permittivity increases with increase of nickel concentration. Increase in temperature enhances the permittivity initially, till 40 degrees C and thereafter the permittivity decreases. The dielectric loss exhibits relaxation peaks and the peaks shift to lower frequencies with increase in volume fraction of the nickel nanoparticles in the matrix. The evaluation of magnetic and dielectric properties of these composites suggests that the dielectric permittivity can be tailored by an appropriate loading of the filler using semi-empirical equations and the magnetic properties vary according to simple mixture equations. (C) 2010 Elsevier B.V. All rights reserved.

}, keywords = {Composite materials, dielectric properties, Elastomers, magnetic properties}, issn = {0254-0584}, doi = {10.1016/j.matchemphys.2010.01.006}, author = {Jamal, E. Muhammad Abdul and Joy, Pattayil Alias and Kurian, Philip and Anantharaman, Maliemadom R.} } @article { ISI:000276615500006, title = {On the magnetic, mechanical and rheological properties of rubber-nickel nanocomposites}, journal = {Polymer Bulletin}, volume = {64}, number = {9}, year = {2010}, month = {MAY}, pages = {907-923}, publisher = {SPRINGER}, address = {233 SPRING ST, NEW YORK, NY 10013 USA}, abstract = {

Rubber-nickel nanocomposites were synthesized by incorporating freshly prepared nanometric nickel particles in two different matrices namely natural rubber and neoprene rubber according to specific recipes for various loadings of nano nickel and the cure characteristics of these composites were evaluated. The maximum torque values register an increase with the increase in loading of nickel in both composites and this is attributed to the non-interacting nature of nickel nanoparticles with rubber matrices. The cure time of natural rubber composites decreases with increase in the content of nickel, and in neoprene rubber cure, time increases with increase in filler content. In natural rubber, the curing reaction seems to be activated by the presence of nickel particles. The magnetization studies of the composites reveal that the magnetic properties of nickel are retained in the composite samples. The elastic modulus of natural rubber and neoprene rubber are largely improved by the incorporation of nickel particles.

}, keywords = {Cure characteristics, Elastic modulus, magnetic properties, Nanocomposites}, issn = {0170-0839}, doi = {10.1007/s00289-009-0231-z}, author = {Jamal, E. Muhammad Abdul and Joy, Pattayil Alias and Kurian, Philip and Anantharaman, Maliemadom R.} } @article { ISI:000300591700013, title = {Effect of inter-particle interactions on the magnetic properties of magnetite nanoparticles after coating with dextran}, journal = {International Journal of Nanotechnology}, volume = {8}, number = {10-12, SI}, year = {2011}, month = {JAN}, pages = {907-915}, publisher = {INDERSCIENCE ENTERPRISES LTD}, address = {WORLD TRADE CENTER BLDG, 29 ROUTE DE PRE-BOIS, CASE POSTALE 896, CH-1215 GENEVA, SWITZERLAND}, abstract = {

Nanoparticles of magnetite (Fe3O4) are synthesised by a coprecipitation method and coated with the biocompatible polymer, dextran. The uncoated and dextran coated magnetite nanoparticles are characterised by powder X-ray diffraction, infrared spectroscopy, transmission electron microscopy, and magnetic measurements. The magnetic properties of the uncoated and coated magnetite nanoparticles are compared to study the effect of inter-particle magnetic interactions on the magnetic characteristics. Absence of magnetic hysteresis at room temperature indicates the superparamagnetic nature of the two samples. Evidence for the effect of reduced inter-particle magnetic interactions is directly obtained from the field dependence of magnetisation at room temperature. The decreased superparamagnetic blocking temperature and the nature and shape of the field cooled magnetisation curve of the dextran coated sample further confirmed that the inter-particle magnetic interactions are completely suppressed after coating.

}, keywords = {dextran coating, magnetic interactions, magnetic properties, magnetite, Nanoparticles}, issn = {1475-7435}, author = {Sreeja, V. and Joy, Pattayil Alias} } @article { ISI:000297352000112, title = {Preparation and characterization of magnetic nanoparticles embedded in hydrogels for protein purification and metal extraction}, journal = {Journal of Polymer Research}, volume = {18}, number = {6}, year = {2011}, note = {International Conference on Advances in Polymer Technology, Cochin Univ Sci \& Technol, Cochin, INDIA, FEB 26-27, 2010}, month = {NOV}, pages = {2285-2294}, publisher = {SPRINGER}, address = {VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS}, abstract = {

The present work involves the development of hydrogel magnetic nanocomposites for protein purification and heavy metal extraction applications. The magnetic nanoparticles (MNPs) were prepared in situ in poly(acrylamide)-gum acacia (PAM-GA) hydrogels. The formation of magnetic nanoparticles in the hydrogel networks was confirmed by Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). Scanning electron (SEM) microscopy studies revealed the formation of MNPs throughout the hydrogel networks. The average size of MNPs formed in the hydrogel networks was 3-5 nm as determined by transmission electron microscopy (TEM). The thermal properties of the hydrogel magnetic nanocomposites were evaluated by dynamic scanning calorimetry (DSC) and thermogravimetric (TG) analysis. The magnetic properties of the developed hydrogel magnetic nanocomposites were determined by a vibrating sample magnetometer (VSM). The swelling properties of the hydrogel and the hydrogel magnetic nanocomposites were studied in detail. The hydrogel magnetic nanocomposites are utilized for the removal of toxic metal ions such as Co(II), Ni(II), and Cu(II) and for protein purification. The results confirm that the hydrogel magnetic nanocomposites exhibit superior extraction properties to hydrogels.

}, keywords = {Bioseparation, Hydrogel, magnetic properties, Metal absorption, Nanocomposite}, issn = {1022-9760}, doi = {10.1007/s10965-011-9642-2}, author = {Nagireddy, Narayana Reddy and Yallapu, Murali Mohan and Kokkarachedu, Varaprasad and Sakey, Ravindra and Kanikireddy, Vimala and Alias, Joy Pattayil and Konduru, Mohana Raju} } @article { ISI:000307039700023, title = {Enhanced magnetic parameters in the morphotropic phase boundary region of nanocrystalline multiferroic Bi1-xLaxFeO3}, journal = {Solid State Communications}, volume = {152}, number = {16}, year = {2012}, month = {AUG}, pages = {1609-1612}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

Antiferromagnetic multiferroic BiFeO3 shows ferromagnetic characteristics by simultaneous substitution of Bi by La and decrease in the particle size to nanometer dimensions. Large changes in saturation and remnant magnetization, magnetic susceptibility at low and high fields, along with some anomalous changes in the magnetic transition temperature are observed in nanocrystalline Bi1-xLaxFeO3 system for 0.1 \<= x \<= 0.2. This compositional region corresponds to the morphotropic phase boundary (MPB) region separating the rhombohedral and orthorhombic phases, and the effect is similar to that observed in many ferroelectric systems. The present observation of enhanced ferromagnetic parameters in the MPB region of the nanocrystalline multiferroic La substituted BiFeO3 system, combined with the known ferroelectric characteristics, is suitable for future device applications. (C) 2012 Elsevier Ltd. All rights reserved.

}, keywords = {Bismuth ferrite, magnetic properties, Multiferroics, Nanocrystalline materials}, issn = {0038-1098}, doi = {10.1016/j.ssc.2012.05.011}, author = {Thakuria, P. and Joy, Pattayil Alias} } @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: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:000337521700013, title = {Large magnetocaloric effect, moment, and coercivity enhancement after coating Ni nanoparticles with Ag}, journal = {ChemPhysChem}, volume = {15}, number = {8}, year = {2014}, month = {JUN}, pages = {1619-1623}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

We observe a large magnetocaloric effect in monodisperse Ni and NicoreAgshell nanoparticles in the superparamagnetic region. The organically passivated Ni nanospheres show a large magnetic entropy change of 0.9 J kg(-1)K for a 3 T magnetic field change. In comparison to the surfactant-coated Ni nanoparticles, the NicoreAgshell nanoparticles show an enhanced coercivity, magnetization, and magnetocaloric effect (1.3 kgK for a 3 T magnetic field change). The coercivity at 10 K increases from 360 Oe for Ni nanoparticles to nearly 610 Oe for NicoreAgshell particles. This large enhancement is attributed to the enhanced inter-particle interaction, which is mediated by the metallic shell, over the relatively weaker dipolar interaction in the surfactant-coated Ni nanoparticles, and to modification of the surface spin structure.

}, keywords = {anisotropy, core-shell, magnetic properties, Nanoparticles, superparamagnetic}, issn = {1439-4235}, doi = {10.1002/cphc.201300886}, author = {Srinath, Sanyadanam and Poddar, Pankaj and Das, Raja and Sidhaye, Deepti and Bhagavatula L. V. Prasad and Gass, James and Srikanth, Hariharan} } @article { ISI:000329479500021, title = {Magnetism in disordered carbon as a function of the extent of graphitization}, journal = {Solid State Communications}, volume = {177}, year = {2014}, month = {JAN}, pages = {89-94}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

Magnetic properties of disordered carbon have been investigated as a function of the extent of graphitization. It is found that the magnetization of the disordered carbon decreases with increasing degree of graphitization. Treatment with acid modifies the magnetic characteristics considerably and the original magnetic characteristics are retained upon further heat treatment. The results show that the intrinsic magnetic behavior of the disordered carbon depends on the microstructure and that the edge states play a critical role in deciding the magnetic interactions in the amorphous carbon system. (C) 2013 Elsevier Ltd. All rights reserved.

}, keywords = {Amorphous carbon, disordered carbon, Graphitization, magnetic properties}, issn = {0038-1098}, doi = {10.1016/j.ssc.2013.09.037}, author = {Raj, K. Govind and Joy, Pattayil Alias} } @article {43792, title = {Synthesis, characterization and electrochemical investigations of mixed-ligand copper(II)-organic supramolecular frameworks}, journal = {Journal of Molecular Structure}, volume = {1147}, year = {2017}, month = {NOV}, pages = {549-557}, type = {Article}, abstract = {

Two mixed-ligand copper(II)-organic coordination compounds with 5,5{\textquoteright}-dimethyl-2,2{\textquoteright}-bipyridine (5,5{\textquoteright}-Me(2)bpy) as a primary ligand while aliphatic malonate (Hmal) and aromatic 2-hydroxynicotinate (2-OHNA) as secondary ligands, were synthesized. These complexes are formulated as: [Cu(Hmal)(5,5{\textquoteright}-Me(2)bPY)(H2O)](ClO4) 1 and [Cu-2(2-OHNA)(2)(5,5{\textquoteright}-Me(2)bpy)(2)(NO3)KNO3) 2. These two complexes were structurally characterized by single crystal X-ray diffraction analysis. Characterization was further supported by powder X-ray diffraction analysis, elemental analyses, FT-IR, FAB-MASS and TGA, DSC studies. Cyclic voltammetric and UV-visible spectral studies of these two complexes have also been done. The electrochemical studies of complex 1 in DMSO and DMF have shown that this complex undergoes quasi reversible diffusion-controlled one-electron transfer reaction without any chemical complication while complex 2 in DMSO undergoes quasi-reversible diffusion-controlled one electron transfer reaction, following EC mechanism. The electrochemical behaviour of complex 2 in DMF is complicated probably due to presence of more than one species in solution phase. (C) 2017 Elsevier B.V. All rights reserved.

}, keywords = {2 {\textquoteright}-bipyridine, 3, 5, 5 {\textquoteright}-dimethyl-2, 5-Tricarboxylic acid, Benzene-1, classification, Co-ordination-Compounds, Crystal-structures, cyclic voltammetry, magnetic properties, metal organic framework, Mixed-ligand complex, pi-pi stacking interaction, Polymers, Secondery Building Unit, Structural data, Supramolecular framework, Ternare Komplexe, X-ray diffraction}, issn = {0022-2860}, doi = {10.1016/j.molstruc.2017.06.128}, author = {Singh, Sandeep K. and Srivastava, Ashish Kumar and Srivastava, Krishna and Banerjee, Rahul and Prasad, Jagdish} } @article {44182, title = {Single step, phase controlled, large scale synthesis of ferrimagnetic iron oxide polymorph nanoparticles by thermal plasma route and their rheological properties}, journal = {Journal of Magnetism and Magnetic Materials}, volume = {449}, year = {2018}, month = {MAR 1}, pages = {232-242}, type = {Article}, abstract = {

In this paper we report single step large scale synthesis of highly crystalline iron oxide nanoparticles viz. magnetite (Fe3O4) and maghemite (gamma-Fe2O3) via gas phase condensation process, where micron sized iron metal powder was used as a precursor. Selective phases of iron oxide were obtained by variation of gas flow rate of oxygen and hence partial pressure of oxygen inside the plasma reactor. Most of the particles were found to possesses average crystallite size of about 20-30 nm. The DC magnetization curves recorded indicate almost super-paramagnetic nature of the iron oxide magnetic nanoparticles. Further, iron oxide nanoparticles were analyzed using Raman spectroscopy, X-ray photoelectron spectroscopy and Mossbauer spectroscopy. In order to explore the feasibility of these nanoparticles for magnetic damper application, rheological studies have been carried out and compared with commercially available Carbonyl Iron (CI) particles. The nanoparticles obtained by thermal plasma route show improved dispersion which is useful for rheological applications. (C) 2017 Elsevier B.V. All rights reserved.

}, keywords = {Iron oxide, magnetic properties, Nano-crystalline materials, Rheological properties, Thermal plasma}, issn = {0304-8853}, doi = {10.1016/j.jmmm.2017.09.056}, author = {Raut, Suyog A. and Mutadak, Pallavi R. and Kumar, Shiv and Kanhe, Nilesh S. and Huprikar, Sameer and Pol, Harshawardhan V. and Phase, Deodatta M. and Bhoraskar, Sudha V. and Mathe, Vikas L.} } @article {46008, title = {Magnetic properties of sintered CoFe2O4-BaTiO3 particulate magnetoelectric composites}, journal = {Ceramics International}, volume = {45}, year = {2019}, month = {JUN}, pages = {12307-12311}, type = {Article}, abstract = {

The magnetic properties of sintered particulate magnetoelectric CoFe2O4 - BaTiO3 composites have been studied. The particulate composites are sintered in the temperature range 1000-1300 degrees C, for a short duration of 10 min. The magnetic transition temperature (T-c) of CoFe2O4 is found to decrease with increasing the sintering temperature and sintering time, as well as on increasing the BaTiO3 content in the composites. Similarly, a reduced saturation magnetization at room temperature, compared to that expected for the CoFe2O4 content, is also observed. Powder X-ray diffraction studies showed the presence of the impurity phase related to the hexagonal ferrite BaFe12O19 in all the composites. Ba2Fe2Ti4O13 is observed as a second impurity phase in the BaTiO3 - rich composites. The present studies suggest that the composition of the piezomagnetic (CoFe2O4) phase in the CoFe2O4 - BaTiO3 magnetoelectric composite is affected during the sintering process.

}, keywords = {composites, magnetic properties, Sintering}, issn = {0272-8842}, doi = {10.1016/j.ceramint.2019.03.145}, author = {Mohan, S. and Joy, P. A.} } @article {46089, title = {Size-controlled cobalt ferrite nanocrystals: magnetically separable reusable nanocatalysts for selective oxidation of styrene}, journal = {ChemistrySelect}, volume = {4}, year = {2019}, month = {JUN }, pages = {6524-6531}, type = {Article}, abstract = {

Superparamagnetic cobalt ferrite (CFO) nanocrystals (NCs) with sizes similar to 6 nm and similar to 4 nm were synthesized using a facile solvothermal method using fatty acids, lauric acid and stearic acid, as the capping agents. The synthesized nanocrystals were well characterized by XRD, FT-IR, XPS, SEM and TEM. The formation mechanism was explored and it was shown that the fatty acid was actually chemisorbed as a carboxylate onto the surface of CFO NCs. The experimental results specify that the size and size distribution of the CFO NCs were highly dependent on the length of fatty acid hydrophobic chain. Corresponding changes of the magnetic properties were investigated by measuring magnetization as a function of field and temperature, which suggest that the CFO NCs were superparamagnetic in nature. The catalytic properties for the oxidation of styrene in organic medium were examined by using the synthesized CFO NCs with sizes similar to 6 nm and similar to 4 nm. The synthesized CFO NCs, well dispersible in organic media, were demonstrated to be highly catalytically active, reached 100\% conversion of styrene in 12 h with similar to 77\% and similar to 82\% selectivity for styrene oxide respectively. The magnetic CFO nanocatalysts were easily separated and recovered from the reaction medium by an external magnet, and reused for several cycles without losing catalytic selectivity for styrene oxide.

}, keywords = {Cobalt ferrite, epoxidation, Fatty acids, magnetic properties, nanocrystals}, issn = {2365-6549}, doi = {10.1002/slct.201900714}, author = {Jeyavani, Vijayakrishnan and Pawar, Sayali and Dadwal, Arun and Joy, Pattayil Alias and Mukherjee, Shatabdi Porel} }