01627nas a2200241   4500008004100000022001400041245009600055210006900151260007300220300001400293490000700307520076800314653001401082653002301096653002701119100002001146700001801166700002001184700001901204700001701223700002201240856012301262       2009                        eng d  a1293-255800aEffect of sintering temperature and thermoelectric power studies of the system MgFe2-xCrxO40 aEffect of sintering temperature and thermoelectric power studies  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcDEC  a2075-20790 v113 a<p>Mixed metal oxides showing the spinel structure exhibit interesting structural and electrical properties. Substances with specific compositions in the system MgFe2-xCrxO4 were synthesized by the simple co-precipitation method and have been investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM) to study the effect of temperature on the size of particles and grains. The infrared spectrum shows, two strong bands around 600 and 500 cm(-1). An elemental composition of one of the samples, MgFeCrO4 was found by energy dispersive X-ray spectroscopy (EDS). The thermoelectric power measurements carried out from room temperature to 500 degrees C, show both n-type and p-type behavior. (C) 2009 Elsevier Masson SAS. All rights reserved.</p>10asynthesis10aTemperature effect10aThermoelectric studies1 aHankare, P., P.1 aVader, V., T.1 aSankpal, U., B.1 aGavali, L., V.1 aSasikala, R.1 aMulla, Imtiaz, S.  uhttps://library.ncl.res.in/content/effect-sintering-temperature-and-thermoelectric-power-studies-system-mgfe2-xcrxo4-001967nas a2200241   4500008004100000022001400041245008400055210006900139260006900208300001200277490000800289520111400297653001301411653001501424653005501439100002001494700001901514700002001533700001801553700001701571700002201588856011501610       2009                        eng d  a0925-838800aGas sensing properties of magnesium ferrite prepared by co-precipitation method0 aGas sensing properties of magnesium ferrite prepared by coprecip  aPO BOX 564, 1001 LAUSANNE, SWITZERLANDbELSEVIER SCIENCE SAcNOV  a270-2720 v4883 a<p>Polycrystalline magnesium ferrite (MgFe(2)O(4)) was prepared by the co-precipitation method. The synthesized compound was characterized for their phase and morphology by X-ray diffraction and scanning electron microscopy, respectively. Conductance responses of the (MgFe(2)O(4)) were measured towards gases like hydrogen sulfide (H(2)S), liquefied petroleum gas (LPG), ethanol vapors (C(2)H(5)OH), SO(x), H(2), NO(x), NH(3), methanol, acetone and petrol. The gas sensing characterstics were obtained by measuring the sensitivity as a function of various controlling factors like operating temperatures and concentrations of gases. It was found that the sensor exhibited various responses towards these gases at different operating temperatures. Furthermore; the MgFe(2)O(4) based sensor exhibited a fast response and a good recovery towards petrol at temperature 250 degrees C. The results of the response towards petrol reveal that (MgFe(2)O(4)) synthesized by a simple co-precipitation method, would be a suitable material for the fabrication of the petrol sensor. (C) 2009 Published by Elsevier B.V.</p>10aFerrites10aGas sensor10aX-ray diffraction and scanning electron microscopy1 aHankare, P., P.1 aJadhav, S., D.1 aSankpal, U., B.1 aPatil, R., P.1 aSasikala, R.1 aMulla, Imtiaz, S.  uhttps://library.ncl.res.in/content/gas-sensing-properties-magnesium-ferrite-prepared-co-precipitation-method-001900nas a2200289   4500008004100000022001400041245011400055210006900169260007300238300001400311490000800325520088700333653002201220653002401242653001301266653002401279653002201303653002201325100002001347700001801367700002001385700002101405700001701426700002101443700002201464856012401486       2010                        eng d  a0304-885300aMagnetic, dielectric and complex impedance spectroscopic studies of nanocrystalline Cr substituted Li-ferrite0 aMagnetic dielectric and complex impedance spectroscopic studies   aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcSEP  a2629-26330 v3223 a<p>Nanocrystalline Li0.5Fe2.5-xCrxO4 (2.5 &lt;= x &gt;= 0) ferrites were prepared by a sol-gel autocombustion route. X-ray diffraction was employed to confirm the cubic spinel phase formation of the ferrites. The lattice parameter decreases with increase in Cr content. The saturation magnetization, coercivity and remanance were studied as a function of Cr content. The dielectric constant and dielectric loss were measured as a function of frequency in the frequency range 20 Hz-1 MHz. Frequency dependence of dielectric constant shows dielectric dispersion due to the Maxwell-Wagner type of interfacial polarization. In order to understand the conduction mechanism, complex impedance measurements were carried out. The substitution of chromium plays an important role in changing the dielectric and magnetic properties of lithium ferrites. (C) 2010 Published by Elsevier B.V.</p>10aComplex impedance10adielectric response10aFerrites10aMagnetic hysteresis10aSol-gel synthesis10aX-ray diffraction1 aHankare, P., P.1 aPatil, R., P.1 aSankpal, U., B.1 aGaradkar, K., M.1 aSasikala, R.1 aTripathi, A., K.1 aMulla, Imtiaz, S.  uhttps://library.ncl.res.in/content/magnetic-dielectric-and-complex-impedance-spectroscopic-studies-nanocrystalline-cr-001812nas a2200265   4500008004100000022001400041245008700055210006900142260006900211300001200280490000800292520091300300653002401213653001301237653001401250653002201264100002001286700002001306700001801326700002201344700001701366700002101383700002101404856012101425       2010                        eng d  a0925-838800aSynthesis and characterization of nanocrystalline zinc substituted nickel ferrites0 aSynthesis and characterization of nanocrystalline zinc substitut  aPO BOX 564, 1001 LAUSANNE, SWITZERLANDbELSEVIER SCIENCE SAcAPR  a256-2600 v4963 a<p>Nanocrystalline zinc substituted nickel ferrites, Ni(1-x)Zn(x)Fe(2)O(4) (0.0 &lt;= x &lt;= 1.0) have been prepared by citrate gel auto-combustion method. The effect of zinc ion content on structural, electrical transport and magnetic properties has been studied. The X-ray diffraction (XRD) pattern revealed that, all the compositions possess single-phase spinel structure. The nano-sized grain structure formation was confirmed by transmission electron microscopy (TEM). The dc electrical resistivity shows the samples are semiconducting in nature. The magnetic measurements showed that the composition Ni(0.6)Zn(0.4)Fe(2)O(4) has maximum saturation magnetization (M(s)) while high coersivity (Hc) for ZnFe(2)O(4). Thermoelectric power measurement study showed that the compounds, with x &lt;= 0.4 are p-type and for x &gt; 0.4 behaves n-type conduction mechanism. (C) 2010 Published by Elsevier B.V.</p>10aElectron microscopy10aMagnetic10aSintering10aX-ray diffraction1 aHankare, P., P.1 aSankpal, U., B.1 aPatil, R., P.1 aMulla, Imtiaz, S.1 aSasikala, R.1 aTripathi, A., K.1 aGaradkar, K., M.  uhttps://library.ncl.res.in/content/synthesis-and-characterization-nanocrystalline-zinc-substituted-nickel-ferrites-002261nas a2200265   4500008004100000022001400041245009400055210006900149260007300218300001100291490000800302520135300310653002601663653002201689653001801711653001801729653002101747100002101768700001801789700002001807700001701827700001701844700001701861856011701878       2012                        eng d  a0926-860X00aEnhanced photocatalytic activity of multi-doped TiO2 for the degradation of methyl orange0 aEnhanced photocatalytic activity of multidoped TiO2 for the degr  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcNOV  a96-1020 v4433 a<p>We report the synergistic effect of dopants like Gd, N and Sin enhancing the photocatalytic activity of TiO2. Nanosized TiO2 doped at both cationic and anionic sites by Gd, N and S exhibited increased photocatalytic activity compared to TiO2 doped with either Gd or N and S. All the doped TiO2 existed as anatase phase and no separate phase due to Gd2O3 was seen up to a Gd concentration of 2%. The particle size as seen from the transmission electron micrograph was similar to 25 nm. The optical absorption property of TiO2 was improved by doping and redshift of the absorption edge is seen for all doped samples compared to pristine TiO2. The red shift of the absorption edge was the highest for the multiple ion-doped sample. Presence of bonded N and S in TiO2 was detected by X-ray photoelectron spectroscopy. Fluorescence lifetime studies indicated an enhanced lifetime for the charge carriers in the doped system compared to pristine TiO2. Photocatalytic activity study showed that the multi-doped sample has the highest activity for the degradation of methyl orange compared to Gd-TiO2, NS-TiO2 and pristine TiO2. The enhanced photocatalytic activity of the multi-doped TiO2 is attributed to factors such as improved optical absorption property and improved lifetime of the charge carriers. (C) 2012 Elsevier B.V. All rights reserved.</p>10aFluorescence lifetime10aGd N S doped TiO210aMethyl orange10aPhotocatalyst10aPhotodegradation1 aCharanpahari, A.1 aUmare, S., S.1 aGokhale, S., P.1 aSudarsan, V.1 aSreedhar, B.1 aSasikala, R.  uhttps://library.ncl.res.in/content/enhanced-photocatalytic-activity-multi-doped-tio2-degradation-methyl-orange-0