Department of Physics
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Item Microstructure and Magnetic Properties of Nano Crystalline Manganese Ferrite Thin Film Fabricated by Pulse Laser Deposition(American Scientific Publishers, 2016) Jaison, Joseph,; Tangsali, R. B; Mahadevan Pillai, V. P.; Choudhary, R. J.; Phase, D. M.; Ganeshan, VNanoparticles of Mn Fe2O4 were chemically synthesized by precipitating the metal ions in aqueous alkaline solution with due optimization of reaction parameters. The XRD data of the powder sample comprising all prominent spinel peaks and clear visibility of ferrite absorption bands in FT-IR spectrum confirm single phase spinal formation. Nano grain size values of the sample derived from XRD data is authenticated by particle size viewed in TEM micrograph. Thin film fabricated from this nano material on quartz substrate by pulse laser deposition technique was characterized using XRD and Raman spectroscopic techniques. The XRD results of fabricated thin film indicate moderate degree of texture. AFM image of the thin film showed nano granular morphology with spherical particles of regular size and uniform distribution. Particle size analysis of AFM data suggest formation of thin film by near uniform clustering of nano grains whose dimensions match that of target material. Magnetic measurements of the textured nanocrystalline ferrite thin film revealed enhancement of magnetic properties. The enrichment of coercivity is explained on the basis of large magnetic anisotropy formation in thin film due to texture enhanced lattice strain and surface disorder.Item Synthesis, Structural and Morphological Property of BaSnO3 Nanopowder Prepared by Solid State Ceramic Method(IOP Publishing Ltd., 2017) John, Jibi; Mahadevan Pillai, V.P; Thomas, Anitta Rose; Philip, Reji; Joseph, Jaison; Muthunatesan, S.; Ragavendran, V.; Prabhu, RadhakrishnaItem Characterization and optical limiting behavior of BaSnO3 powder prepared by the conventional solid state method(Elsevier Ltd, 2020) John, Jibi; Chalana, S.R.; Mahadevan Pillai, V.P.; Joseph, Jaison; Muthunatesan, S.; Ragavendran, V.; Tiwari, GargiBaSnO3 powder was prepared by the conventional solid state ceramic method. The structural, morphological, thermodynamical and non linear optical properties of the prepared powder were studied using techniques such as XRD, SEM, TEM and photoluminenscence spectra. XRD analysis reveals, that the prepared powder is polycrystalline in nature with cubic BaSnO3 phase. SEM and AFM analysis also support the XRD analysis. The optimized structure and the comparison of FT-IR and FT-RAMAN spectra were done. The thermodynamical property of the prepared sample was measured. Photoluminenscence spectrum reveals that there is an intense red emission in the visible region. The thermodynamic functions like enthalpy, entropy and heat capacity were found to increase with increasing temperature. There is an optical limiting behavior for the sample which is comparable to that of graphene and its metal hybrids.Item Swelling and DC Conductivity Behaviour of Gelatin-Based Ferrogels(Springer Nature, 2021) Lawrence, Mathias B.; Joseph, Jaison; Usapkar, Twinkle; Azavedo, FirmanGelatin-based systems have great potential in bio-medical applications. Here, we report the solvent uptake and DC conductivity of glutaraldehyde-crosslinked gelatin hydrogels and ferrogels. Both the parameters are found to depend on cross-linker (glutaraldehyde) and dopant (carbonyl iron) concentrations. Higher cross-linker proportions cause decrease in solvent uptake, equilibrium swelling ratio and DC conductivity. Solvent uptake is seen to increase while equilibrium swelling ratio and DC conductivity decrease with dopant concentration in the ferrogels. The solvent uptake and DC conductivity behaviour of the studied systems are explained on the basis of variations in pore size and polymer segmental mobility which, themselves, are functions of cross-linker and dopant concentrations. The diffusion process in the hydrogels and ferrogels obeys the second-order kinetic model.Item Spectroscopic, thermal and sorption characterization of poly(vinyl alcohol)-borax hydrogels with incorporated turmeric(Springer Nature, 2025) Lawrence, Mathias B.; Joseph, JaisonIn this work, three sets of poly(vinyl alcohol) hydrogels, cross-linked using borax, with incorporated turmeric have been synthesized. Their water content, spectroscopic, thermal and sorption properties have been studied, as functions of borax and turmeric concentrations. The water content of the hydrogels decreases due to the presence of turmeric. The Fourier Transform Infra-red (FT-IR) and Raman spectroscopic measurements confirm the incorporation of turmeric in the matrices. Turmeric does not chemically bond with the polymer hydrogel network but is confined to the solvent phase within the pores. The presence and concentration of turmeric significantly affect the adsorption of water molecules onto the polymer backbone. Glass transition temperature and solvent uptake are affected by the concentration of borax and turmeric in the matrices. The sorption behaviour obeys the second-order kinetic model. The observed modifications in properties are caused by the structural re-arrangement of the polymer chains and the re-organization of borate cross-links due to the presence of turmeric.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.