Department of Physics
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Item Characterization and Mössbauer Study of Ni0.45Zn0.55Fe2O4 Nanoparticles Prepared by Novel Precursor Method(American Institute of Physics, 2011) Kothawale, M. M.; Tangsali, R. B.; Joseph, Jaison; Naik, G. K.; Budkuley, J. S.; Meena, Sher Singh; Yusuf, S. M.; Yakhmi, J. V.Nanoparticles of were chemically synthesized by novel precursor method at low temperature. Average particles size was found to be 37 nm. The Mössbauer spectroscopy studies were carried out on the sample for the investigation of magnetic and structural arrangement of Fe in the nano‐crystalline ferrite samples. The values of isomer shift are consistent with Fe ions in trivalent state. The low values of the quadrupole splitting identifies that the local symmetry of the magnetic phase of A—sites is close to cubic while that of B—site is close to trigonal. The broad collapsing sextet B1 can be correlated to the presence of relaxation effect in the sample.Item Magnetic Properties of Textured Nanocrystalline Mn-Zn Ferrite Thin Films Fabricated by Pulsed Laser Deposition.Thin Films Fabricated by Pulsed Laser Deposit(Natural Sciences Publishing, 2014) Joseph, Jaison; Tangsali, R. B.; Choudhary, R. J.; Phase, D. M.; Ganeshan, V.MnxZn1-xFe2O4 nanoparticles were chemically synthesized by co- precipitating metal ions in alkaline aqueous solutions. The XRD peaks match up to spinel ferrites without any multi phase indication and clear visibility of ferrite FT-IR absorption bands confirm single phase spinal formation. Particle size derived from XRD data is authenticated by TEM micrographs. Thin films fabricated from this material on quartz substrate by pulse laser deposition were characterised using XRD. The XRD data revealed formation of spinel structure with a reasonable degree of texture. AFM analysis confirms nano granular film morphology with dimensions comparable to that of target grain. Magnetic data obtained from textured nanocrystalline Mn-Zn ferrite thin film measurements made known enhanced coercivity. The observed enhanced coercivity is explained with due consideration of film texture and surface disorder that originated from Mn concentration specific initial adsorption prior to nucleation, resulting in directional film growth.Item Microstructure and magnetic properties of patterned nano crystalline zinc ferrite thin film fabricated by pulse laser deposition(Elsevier, 2015) Joseph, Jaison; Tangsali, R. B.; Mahadevan Pillai, V. P.; Choudhary, R. J.; Phase, D. M.; Ganeshan, V.Patterned nano crystalline ZnFe2O4 thin film was fabricated on quartz substrate by pulse laser deposition. XRD and Raman spectroscopic techniques were employed for structural characterization of the film. Silencing of a small number of prominent ferrite XRD peaks in thin film signify mild textured film growth. The observed XRD peak position swing with respect to the target material in thin film indicates formation of lateral strain in opposite directions during film growth. The thin film XRD peak position shift with target material data as reference is explained by suggesting an appropriate film growth model. Designated ferrite Raman emission peaks originated from film surface authenticates the stoichiometric and structural stability of ferrite material. AFM images indicate specific pattern formation with nanogranular morphology. Magnetic property measurements of the thin film revealed enhanced properties which are explained on the basis of texture, lattice strain, and surface features that are originated from patterned thin film growth.Item Synthesis, characterization and Transport properties of CoxZn1-xFe2O4 Nanoparticles(IOP Publishing Ltd., 2015) Joseph, Jaison; Tangsali, R. B.; Gurav, S. M.Spinel ferrites are commercially important materials due to their excellent electrical and magnetic properties. Mixed metal spinel ferrites, essentially with low hysteresis loss and small particle sizes, have found new applications in areas like biosensors, drug delivery systems, and hyperthermia. The electrical conductivity, which gives credible information about conduction mechanism, is one of the important properties of ferrites. The order of magnitude of conductivity greatly influences the dielectric and magnetic behavior of the ferrites and depends on the preparative method. The present work deals with investigations into electrical, dielectric and thermo power parameters of CoxZn1-xFe2O4 ferrite nano particles synthesized by co-precipitation method. The effect of variation of the cobalt concentration in the sample on transport properties of nano ferrites has been analyzed.Item Structure and magnetic properties of highly textured nanocrystalline Mn–Zn ferrite thin film(Elsevier, 2015) Joseph, Jaison; Tangsali, R. B.; Mahadevan Pillai, V. P.; Choudhary, R. J.; Phase, D. M.; Ganeshan, V.Nanoparticles of Mn0.2Zn0.8Fe2O4 were chemically synthesized by co-precipitating the metal ions in aqueous solutions in a suitable alkaline medium. The identified XRD peaks confirm single phase spinal formation. The nanoparticle size authentication is carried out from XRD data using Debye Scherrer equation. Thin film fabricated from this nanomaterial by pulse laser deposition technique on quartz substrate was characterized using XRD and Raman spectroscopic techniques. XRD results revealed the formation of high degree of texture in the film. AFM analysis confirms nanogranular morphology and preferred directional growth. A high deposition pressure and the use of a laser plume confined to a small area for transportation of the target species created certain level of porosity in the deposited thin film. Magnetic property measurement of this highly textured nanocrystalline Mn–Zn ferrite thin film revealed enhancement in properties, which are explained on the basis of texture and surface features originated from film growth mechanism.Item Resistivity–thermopower correlation derived temperature-dependent transport behaviour of MnxZn1−xFe2O4 nanoparticles(Taylor & Francis, 2017) Joseph, Jaison; Tangsali, R. B; Gurav, S. M.Ferrite material nanoparticles comprised of manganese and zinc were chemically synthesized by the co-precipitation method. The designated ferrite X-ray diffraction peaks and characteristic ferrite absorption bands in Fourier transform infrared absorption spectra confirmed the formation of a spinel structure. Determination of the full width at half maximum values of the X-ray diffraction peaks and the corresponding calculations using the Scherrer formula suggested the generation of nano-grains. Micrographs obtained using a transmission electron microscope confirmed the nano-scale dimensions of the particles. Deviations in the characteristic resistivity and thermopower values in response to ambient sample temperature variations were experimentally observed and used for correlation-derived temperature-dependent transport behaviour analysis. Samples with a concentration x = 0.8 and 1.0 showed high thermopower values at reasonably low temperatures with moderate specific resistance.Item D.C. conductivity behaviour of poly(vinyl alcohol)-based ferrogels: role of borax and carbonyl iron(Springer Nature, 2019) Lawrence, Mathias B.; Joseph, Jaison; Phondekar, Karesh; Moodi, KiranThe d.c. conductivity of poly(vinyl alcohol) hydrogels and ferrogels, cross-linked with borax, has been studied using two-probe resistance measurement method as a function of cross-linker and dopant concentrations. The availability of charge carriers (i.e. unbound borate ions and free sodium ions) in these matrices is seen to vary with cross-linker and dopant concentrations. Increase in borax concentration leads to the rise in d.c. conductivity values. Enhancement in the carbonyl iron dopant proportions, at unchanged borax concentrations, causes a decrease in the conductivity. This behaviour is explained on the basis of structural modifications introduced within the network matrix owing to the variations in cross-linker and dopant concentrations.