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Papers by balesh kumar Vashisth

Crystal Research and Technology, 2011

ABSTRACT Room temperature crystal structure, ferroelectric and magnetic properties of polycrystal... more ABSTRACT Room temperature crystal structure, ferroelectric and magnetic properties of polycrystalline Bi0.85Sm0.15FeO3 samples were investigated. X-ray diffraction study shows that the compound possesses a dominant PbZrO3-like orthorhombic structure with √2a ×2√2a ×2a superlattice (a is the parameter of the cubic perovskite subcell). In contrast to piezoresponse force microscopy data demonstrating some features characteristic of ferroelectrics, polarization vs. electric field measurements reveal the behavior expected for nonpolar materials. Investigation of magnetic properties confirms that 15% samarium substitution suppresses the spin modulation typical of BiFeO3 and induces the appearance of spontaneous magnetization. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Ceramics International, 2018

Multiferroic nano-composites (1-x) Bi .9 Pr .1 FeO 3 (BPFO)-x Ni .5 Zn .5 Fe 2 O 4 (NZFO) for x =... more Multiferroic nano-composites (1-x) Bi .9 Pr .1 FeO 3 (BPFO)-x Ni .5 Zn .5 Fe 2 O 4 (NZFO) for x = 0.0, 0.1, 0.2, 0.3 and 1.0 were synthesized by sol-gel auto-combustion method. Detailed investigations were made on the structural, morphological, ferroelectric, magnetic and dielectric properties of these nano-composites. The X-ray Diffraction pattern confirms the coexistence of perovskite BPFO and spinel NZFO phases without any impurity. The average particle size of as prepared BPFO and NZFO nanoparticles is nearly equal to 110 nm and 35 nm respectively which have been confirmed by the XRD and Transmission Electron Microscopy analysis. Structural and surface morphology are studied by Scanning Electron Microscopy. The dielectric properties of the composites are also studied at room temperature. The magnetic hysteresis loop has been studied to know the magnetic response of samples to the applied magnetic field of ± 1 T at room temperature. The saturation and remnant magnetization are found to increase with increase in NZFO weight percentage in the composite. The saturation magnetization values are 8.57 emu/g, 16.71 emu/g, 24.41 emu/g and remnant magnetization values are 0.78 emu/g, 1.23 emu/g, 1.58 emu/g for BPFO-NZFO 1, 2, 3 composite samples respectively. An anomalous ferroelectric behavior of BPFO-NZFO 1 composite sample was observed which can be understand with the help of observed results in dielectric and morphology of the samples. The incorporation of BPFO and NZFO enhances the multiferroic properties in the present composite materials which are quite promising from application point of view.

Journal of Alloys and Compounds, 2018

Abstract Multiferroics composite of perovskite BiFeO3 and spinel ferrites NiFe2O4/ZnFe2O4/CoFe2O4... more Abstract Multiferroics composite of perovskite BiFeO3 and spinel ferrites NiFe2O4/ZnFe2O4/CoFe2O4 with different composition were prepared by sol-gel method. Detailed investigations were made on the structural, magnetic and ferroelectric properties of these composites. The X-Ray Diffraction pattern confirms the formation of distorted perovskite and spinel phases of BiFeO3 and NiFe2O4, ZnFe2O4, CoFe2O4 respectively. Transmission Electron Microscopy (TEM) images reveals the particle size and the elemental idea of phase formation. The particle sizes calculated using TEM of NiFe2O4, ZnFe2O4, CoFe2O4 are 10–20 nm, 20–30 nm, 15–25 nm respectively and these are compatible with XRD results. The results of Scanning Electron Microscopy (SEM) images reveal that all the samples exhibit a very uniform distribution of perovskite and spinel phases in composites. The modified microstructure of composites is effective in reducing the leakage of electric charges which occurs due to a chain formation of the spinel-ferrite phase particle, so the electrical, magnetic and ferroelectric properties of composites may improve with spinel ferrites content.

Advanced Materials Letters, 2018

Pure BiFeO3 (BFO) nanoparticles were prepared using various complexing agents like citric acid, m... more Pure BiFeO3 (BFO) nanoparticles were prepared using various complexing agents like citric acid, malonic acid, succinic anhydride and tartaric acid by sol-gel method annealed at different temperatures (400  C, 500  C, 600  C). X-Ray diffraction pattern of various samples show the degree of formation of required phase. Particle size of pure phase BFO has been shown using TEM image. Scanning Electron Microscopy studies for different samples give detailed study of morphology of samples. Ferroelectric and magnetic studies of best prepared samples show their comparative multiferroic properties. Dielectric analysis also shows the variation in dielectric loss, real and imaginary part of permittivity versus frequency at room temperature.

Your article is protected by copyright and all rights are held exclusively by Springer Science+Bu... more Your article is protected by copyright and all rights are held exclusively by Springer Science+Business Media, LLC. This e-offprint is for personal use only and shall not be selfarchived in electronic repositories. If you wish to self-archive your work, please use the accepted author's version for posting to your own website or your institution's repository. You may further deposit the accepted author's version on a funder's repository at a funder's request, provided it is not made publicly available until 12 months after publication.

Journal of Alloys and Compounds, 2017

Crystal Research and Technology, 2011

ABSTRACT Room temperature crystal structure, ferroelectric and magnetic properties of polycrystal... more ABSTRACT Room temperature crystal structure, ferroelectric and magnetic properties of polycrystalline Bi0.85Sm0.15FeO3 samples were investigated. X-ray diffraction study shows that the compound possesses a dominant PbZrO3-like orthorhombic structure with √2a ×2√2a ×2a superlattice (a is the parameter of the cubic perovskite subcell). In contrast to piezoresponse force microscopy data demonstrating some features characteristic of ferroelectrics, polarization vs. electric field measurements reveal the behavior expected for nonpolar materials. Investigation of magnetic properties confirms that 15% samarium substitution suppresses the spin modulation typical of BiFeO3 and induces the appearance of spontaneous magnetization. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Ceramics International, 2018

Multiferroic nano-composites (1-x) Bi .9 Pr .1 FeO 3 (BPFO)-x Ni .5 Zn .5 Fe 2 O 4 (NZFO) for x =... more Multiferroic nano-composites (1-x) Bi .9 Pr .1 FeO 3 (BPFO)-x Ni .5 Zn .5 Fe 2 O 4 (NZFO) for x = 0.0, 0.1, 0.2, 0.3 and 1.0 were synthesized by sol-gel auto-combustion method. Detailed investigations were made on the structural, morphological, ferroelectric, magnetic and dielectric properties of these nano-composites. The X-ray Diffraction pattern confirms the coexistence of perovskite BPFO and spinel NZFO phases without any impurity. The average particle size of as prepared BPFO and NZFO nanoparticles is nearly equal to 110 nm and 35 nm respectively which have been confirmed by the XRD and Transmission Electron Microscopy analysis. Structural and surface morphology are studied by Scanning Electron Microscopy. The dielectric properties of the composites are also studied at room temperature. The magnetic hysteresis loop has been studied to know the magnetic response of samples to the applied magnetic field of ± 1 T at room temperature. The saturation and remnant magnetization are found to increase with increase in NZFO weight percentage in the composite. The saturation magnetization values are 8.57 emu/g, 16.71 emu/g, 24.41 emu/g and remnant magnetization values are 0.78 emu/g, 1.23 emu/g, 1.58 emu/g for BPFO-NZFO 1, 2, 3 composite samples respectively. An anomalous ferroelectric behavior of BPFO-NZFO 1 composite sample was observed which can be understand with the help of observed results in dielectric and morphology of the samples. The incorporation of BPFO and NZFO enhances the multiferroic properties in the present composite materials which are quite promising from application point of view.

Journal of Alloys and Compounds, 2018

Abstract Multiferroics composite of perovskite BiFeO3 and spinel ferrites NiFe2O4/ZnFe2O4/CoFe2O4... more Abstract Multiferroics composite of perovskite BiFeO3 and spinel ferrites NiFe2O4/ZnFe2O4/CoFe2O4 with different composition were prepared by sol-gel method. Detailed investigations were made on the structural, magnetic and ferroelectric properties of these composites. The X-Ray Diffraction pattern confirms the formation of distorted perovskite and spinel phases of BiFeO3 and NiFe2O4, ZnFe2O4, CoFe2O4 respectively. Transmission Electron Microscopy (TEM) images reveals the particle size and the elemental idea of phase formation. The particle sizes calculated using TEM of NiFe2O4, ZnFe2O4, CoFe2O4 are 10–20 nm, 20–30 nm, 15–25 nm respectively and these are compatible with XRD results. The results of Scanning Electron Microscopy (SEM) images reveal that all the samples exhibit a very uniform distribution of perovskite and spinel phases in composites. The modified microstructure of composites is effective in reducing the leakage of electric charges which occurs due to a chain formation of the spinel-ferrite phase particle, so the electrical, magnetic and ferroelectric properties of composites may improve with spinel ferrites content.

Advanced Materials Letters, 2018

Pure BiFeO3 (BFO) nanoparticles were prepared using various complexing agents like citric acid, m... more Pure BiFeO3 (BFO) nanoparticles were prepared using various complexing agents like citric acid, malonic acid, succinic anhydride and tartaric acid by sol-gel method annealed at different temperatures (400  C, 500  C, 600  C). X-Ray diffraction pattern of various samples show the degree of formation of required phase. Particle size of pure phase BFO has been shown using TEM image. Scanning Electron Microscopy studies for different samples give detailed study of morphology of samples. Ferroelectric and magnetic studies of best prepared samples show their comparative multiferroic properties. Dielectric analysis also shows the variation in dielectric loss, real and imaginary part of permittivity versus frequency at room temperature.

Your article is protected by copyright and all rights are held exclusively by Springer Science+Bu... more Your article is protected by copyright and all rights are held exclusively by Springer Science+Business Media, LLC. This e-offprint is for personal use only and shall not be selfarchived in electronic repositories. If you wish to self-archive your work, please use the accepted author's version for posting to your own website or your institution's repository. You may further deposit the accepted author's version on a funder's repository at a funder's request, provided it is not made publicly available until 12 months after publication.

Journal of Alloys and Compounds, 2017