In this work, the synthesis of ZnFe2O4 (ZF) through mediation of different polymers e.g., Polyvin... more In this work, the synthesis of ZnFe2O4 (ZF) through mediation of different polymers e.g., Polyvinyl alcohol (PVA), Polyvinylpyrrolidone (PVP) and Polyethylene glycol (PEG) were studied. The structural, micro-structural, thermal and dielectric properties were investigated. Structural characterization, XRD through Rietveld refinement confirms its face centred cubic structure. The thermal analysis of ZF through TGA /DSC signified the stability of ZF. FTIR gave the confirmation regarding the functional group associated with ZF. The Dielectric measurements were carried out by varying the frequency from 20Hz to 2MHz, the dielectric constant decreases with increase in frequency & Tanδ shows highly decrement values. The scaling of relaxation behaviour have been rigorously analysed through Impedance, Modulus and Conductivity Spectroscopy in the temperature and frequency range of 30˚C-200˚C, 20Hz - 2MHz respectively. Scaling of parameters shows the temperature independent relaxation behaviour...
The universal percolation behavior i.e. reff ðx; fconfc Þ/ x x and eeff ðx; fconfc Þ/ x � y is sa... more The universal percolation behavior i.e. reff ðx; fconfc Þ/ x x and eeff ðx; fconfc Þ/ x � y is satisfied; with 28 x + y = 1, where reff is the effective ac conductivity of the composite, x is the frequency of applied ac sig- 29 nal and fc is percolation threshold. The exponents (x = 0.72 and y = 0.28) obtained under the inter-cluster 30 polarization model for the case of 3D systems are consistent with the experimental values. The critical 31 exponents s, s0 and t which characterize the divergence of eeff and reff in the vicinity of fc show non-uni- 32 versal values. The non-universality of s, s 0 and t is correlated with the extent of spatial connectivity of fil- 33 ler particles, which is reflected from the experimental values of loss tangent.
The micro-structural features and the optical properties of polymer blends (PB) of polyvinylidene... more The micro-structural features and the optical properties of polymer blends (PB) of polyvinylidene fluoride (PVDF) base with polyethylene glycol (PEG) and polymer nanocomposites (PNC) of PVDF base with graphene oxide (GO) as fillers are compared. Different weight fractions of PVDF/PEG and PVDF/GO samples were prepared through solution casting followed by spin coating. The microstructure of PVDF/PEG and PVDF/GO shows formation of immiscible/compatible/ homogenous microstructures over different extents of loading of the filler components. UV-Visible spectrometry revealed an increase in absorbance with the amount of filler and the absorbance was found to be lesser and highly dispersive for the PB as compared to PNC, attributed to the heterogeneity/electrical conductivity of the respective fillers of the two systems. Spectroscopic ellipsometry was used to study the various optical constants (e.g. refractive index, extinction co-efficient, etc.) & their dispersion behavior over the visibl...
In this manuscript, the dielectric behavior of a variety of ferroelectric polymer dielectrics (FP... more In this manuscript, the dielectric behavior of a variety of ferroelectric polymer dielectrics (FPD), which may bethe materials for future electrostatic energy storage application shave been discussed. The variety of polymer dielectrics, comprising of ferroelectric polymer[polyvinylidene fluoride (PVDF)]/non-polarpolymer [low density polyethylene (LDPE)] and different sizes of metal particles (Ni, quasicrystal of Al-Cu-Fe) as filler, were prepared through different process conditions (cold press/hot press) and are investigated experimentally. Very high values of effective dielectric constants (eeff) with low loss tangent (Tan δ) were observed forall the prepared FPD at their respective percolation thresholds (fc). The enhancement of eeff and Tan δ at the insulator to metal transition (IMT) is explained through the boundary layer capacitor effect and the percolation theory respectively. The non-universal fc/critical exponents across the IMT have been explained through percolation theory andis attributed to ...
In this work, the synthesis of ZnFe2O4 (ZF) through mediation of different polymers e.g., Polyvin... more In this work, the synthesis of ZnFe2O4 (ZF) through mediation of different polymers e.g., Polyvinyl alcohol (PVA), Polyvinylpyrrolidone (PVP) and Polyethylene glycol (PEG) were studied. The structural, micro-structural, thermal and dielectric properties were investigated. Structural characterization, XRD through Rietveld refinement confirms its face centred cubic structure. The thermal analysis of ZF through TGA /DSC signified the stability of ZF. FTIR gave the confirmation regarding the functional group associated with ZF. The Dielectric measurements were carried out by varying the frequency from 20Hz to 2MHz, the dielectric constant decreases with increase in frequency & Tanδ shows highly decrement values. The scaling of relaxation behaviour have been rigorously analysed through Impedance, Modulus and Conductivity Spectroscopy in the temperature and frequency range of 30˚C-200˚C, 20Hz - 2MHz respectively. Scaling of parameters shows the temperature independent relaxation behaviour...
The universal percolation behavior i.e. reff ðx; fconfc Þ/ x x and eeff ðx; fconfc Þ/ x � y is sa... more The universal percolation behavior i.e. reff ðx; fconfc Þ/ x x and eeff ðx; fconfc Þ/ x � y is satisfied; with 28 x + y = 1, where reff is the effective ac conductivity of the composite, x is the frequency of applied ac sig- 29 nal and fc is percolation threshold. The exponents (x = 0.72 and y = 0.28) obtained under the inter-cluster 30 polarization model for the case of 3D systems are consistent with the experimental values. The critical 31 exponents s, s0 and t which characterize the divergence of eeff and reff in the vicinity of fc show non-uni- 32 versal values. The non-universality of s, s 0 and t is correlated with the extent of spatial connectivity of fil- 33 ler particles, which is reflected from the experimental values of loss tangent.
The micro-structural features and the optical properties of polymer blends (PB) of polyvinylidene... more The micro-structural features and the optical properties of polymer blends (PB) of polyvinylidene fluoride (PVDF) base with polyethylene glycol (PEG) and polymer nanocomposites (PNC) of PVDF base with graphene oxide (GO) as fillers are compared. Different weight fractions of PVDF/PEG and PVDF/GO samples were prepared through solution casting followed by spin coating. The microstructure of PVDF/PEG and PVDF/GO shows formation of immiscible/compatible/ homogenous microstructures over different extents of loading of the filler components. UV-Visible spectrometry revealed an increase in absorbance with the amount of filler and the absorbance was found to be lesser and highly dispersive for the PB as compared to PNC, attributed to the heterogeneity/electrical conductivity of the respective fillers of the two systems. Spectroscopic ellipsometry was used to study the various optical constants (e.g. refractive index, extinction co-efficient, etc.) & their dispersion behavior over the visibl...
In this manuscript, the dielectric behavior of a variety of ferroelectric polymer dielectrics (FP... more In this manuscript, the dielectric behavior of a variety of ferroelectric polymer dielectrics (FPD), which may bethe materials for future electrostatic energy storage application shave been discussed. The variety of polymer dielectrics, comprising of ferroelectric polymer[polyvinylidene fluoride (PVDF)]/non-polarpolymer [low density polyethylene (LDPE)] and different sizes of metal particles (Ni, quasicrystal of Al-Cu-Fe) as filler, were prepared through different process conditions (cold press/hot press) and are investigated experimentally. Very high values of effective dielectric constants (eeff) with low loss tangent (Tan δ) were observed forall the prepared FPD at their respective percolation thresholds (fc). The enhancement of eeff and Tan δ at the insulator to metal transition (IMT) is explained through the boundary layer capacitor effect and the percolation theory respectively. The non-universal fc/critical exponents across the IMT have been explained through percolation theory andis attributed to ...
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Papers by Maheswar Panda