Sushant Gupta | University of Lucknow (original) (raw)

Papers by Sushant Gupta

Bulk superconductor samples of YBa2Cu3-xZnxO7-{\delta} with x = 0, 0.01, 0.03 are synthesized by ... more Bulk superconductor samples of YBa2Cu3-xZnxO7-{\delta} with x = 0, 0.01, 0.03 are synthesized by solid-state reaction route. The structural characterisation of all samples has been carried out by x-ray-diffraction (XRD) and transmission electron microscopy (TEM) techniques. The x-ray diffraction patterns indicate that the gross structure/phase of YBa2Cu3-xZnxO7-{\delta} do not change with the substitution of Zn up to x=0.03. In TEM investigations of Zn-doped Y-based cuprates a number of ZnO nano-flower and nano-rod of Y-211 phase are found dispersed in regular YBa2Cu3-xZnxO7 matrix. These dispersed nano-flowers of ZnO and nano-rods of Y-211 phase may serve as flux-pinning centers. These pinning centers enhance critical current density (Jc) value of these HTSC samples.

Bulk samples of (Sn1−xSbxO2−delta)(Sn_{1-x}Sb_{x}O_{2-\delta})(Sn1−xSbxO2−delta) with x = 0.00, 0.10, 0.20, 0.30 are synthesized by... more Bulk samples of (Sn1−xSbxO2−delta)(Sn_{1-x}Sb_{x}O_{2-\delta})(Sn1−xSbxO2−delta) with x = 0.00, 0.10, 0.20, 0.30 are synthesized by solid-state reaction route. Samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV-Vis spectroscopy. The x-ray diffraction patterns indicate that the gross structure/phase of (Sn1−x(Sn_{1-x}(Sn1−x SbxO2−delta)Sb_{x}O_{2-\delta})SbxO2−delta) do not change with the substitution of antimony (Sb) up to x = 0.30. The surface morphological examination with SEM revealed the fact that the grain size in the antimony doped sample is larger than that of undoped one and hence pores/voids between the grains increase with Sb concentration up to 0.30. TEM image of undoped sample indicates that the SnO2SnO_{2}SnO2 grains have diameters ranging from 25 to 120 nm and most grains are in cubic or spherical shape. As antimony content increases, the nanocubes/spheres are converted into microcubes/spheres. The reflectance of Sn1−xSbxO2−deltaSn_{1-x}Sb_{x}O_{2-\delta}Sn1−xSbxO2−delta samples increases whereas absorbance of these samples decreases with the increased concentration of antimony (Sb) for the wavelength range 360 - 800 nm. The energy bandgap of Sb doped - SnO2SnO_{2}SnO2 samples were obtained from optical absorption spectra by UV-Vis absorption spectroscopy. Upon increasing the Sb concentration the bandgap of the samples was found to increase from 3.367 eV to 3.558 eV.

Many of the general-relativity-tests such as bending of light near a star and gravitational red/b... more Many of the general-relativity-tests such as bending of light near a star and gravitational red/blue shift are explained without general-relativity & without Newtonian-approach. The authors first cast doubts on both, the Newtonian and the relativistic approach; and proposes a novel alternative-explanation. The new alternative explanation is based on refraction-phenomenon of optics. Estimation of results, with new approach, are in agreement with known values. Though physics is different, but it is argued that general-relativity based gravitational-bending and refraction-based bending have more in common than is generally realized. Also discussed are black-hole and gravitational-lensing in the new perspective of refraction. The new refraction-based theory makes a few new predictions and also suggests a few tests..

Integrated Ferroelectrics, 2011

Bulk superconductor samples of YBa2Cu3-xCoxO7-δ with x = 0, 0.01, 0.03, 0.05 are synthesized by s... more Bulk superconductor samples of YBa2Cu3-xCoxO7-δ with x = 0, 0.01, 0.03, 0.05 are synthesized by solid-state reaction route. Both x-ray diffraction and electron microscopy have been employed to study the phase identification, intergrowths, dislocations and the local structure of these samples. Transition temperature of the samples has been determined by four probe resistivity measurements. The x-ray diffraction patterns indicate that the gross structure/phase of YBa2Cu3-xCoxO7-δ do not change with the substitution of Co up to x = 0.05. The zero resistance critical transition temperature [Tc(R = 0)] is found to decrease and critical current density (Jc) increases with the increased concentration of cobalt in the compound. The Jc enhancement for the cobalt doped samples may be resulting due to flux pinning from some defects such as planar defects, stacking faults and micro defects (twin, domains etc.) and the rapid suppression in Tc may be due to the cooper pair breaking and the hole filling in the CuO2 planes.


`Zero-spin-photon hypothesis' as proposed in an earlier paper [1] states that: `due to inevitable... more `Zero-spin-photon hypothesis' as proposed in an earlier paper [1] states that: `due to inevitable consequence of the second-law of thermodynamics and spin-conservation, the `zero-spin-photon' is generated in pair-production process (of elementary particles), which decays into neutrino and antineutrino'. The zero-spin photon hypothesis explains [1] several riddles of physics and universe. In the present paper, it is shown that `the zero-spin photon hypothesis' when incorporated into the higer-order Feynman diagram (with a closed-loop) could possibly solve the half-a-century-old and famous `infinity-problem' of QED, and thus could avoid the need of the so called `re-normalization' procedure.


`What is work and what is heat' is re-investigated from the perspective of second law of thermody... more `What is work and what is heat' is re-investigated from the perspective of second law of thermodynamics. It is shown that the inevitable consequence of second law of thermodynamics and spin conservation necessitates the possible generation of zero spin photon in pair production process, and its subsequent decay explains the birth of neutrino and antineutrino. The proposed neutrino-genesis, solves many riddles of physics and universe. The riddles considered and explained are about: (i) mysterious neutrino (and antineutrino) and its bizarre properties such as handed-ness and parity-violation, (ii) questionable asymmetry/ excess of matter over antimatter, (iii) possibility of existence of antimatter world and (iv) parity (P) violation and aspects of CP and CPT violation or restoration in the universe.

In the present paper a new concept is introduced that: `mass is a complex quantity'. The concept ... more In the present paper a new concept is introduced that: `mass is a complex quantity'. The concept of complex-mass suggests that the total mass M of a moving body is complex sum of: (i) the real-part (grain or rest) mass mgm_{g}mg establishing its particle behaviour and (ii) the imaginary-part mass mpm_{p}mp governing its wave properties. Mathematically, the complex mass M=mg+impM = m_{g} + im_{p}M=mg+imp; the magnitude $\mid M \mid = (m_{g}^{2} + m_{p}^{2})^{{1/2}}. The theory proposed here explains successfully several effects such as `Compton effect' and `refraction of light' which could not be explained otherwise by a single theory of wave or particle. Also explained are `Doppler effect for light', `photo-electric effect', `Uncertainty principle', `Relativity' and `supersymmetry'

Bulk superconductor samples of YBa2Cu3-xZnxO7-{\delta} with x = 0, 0.01, 0.03 are synthesized by ... more Bulk superconductor samples of YBa2Cu3-xZnxO7-{\delta} with x = 0, 0.01, 0.03 are synthesized by solid-state reaction route. The structural characterisation of all samples has been carried out by x-ray-diffraction (XRD) and transmission electron microscopy (TEM) techniques. The x-ray diffraction patterns indicate that the gross structure/phase of YBa2Cu3-xZnxO7-{\delta} do not change with the substitution of Zn up to x=0.03. In TEM investigations of Zn-doped Y-based cuprates a number of ZnO nano-flower and nano-rod of Y-211 phase are found dispersed in regular YBa2Cu3-xZnxO7 matrix. These dispersed nano-flowers of ZnO and nano-rods of Y-211 phase may serve as flux-pinning centers. These pinning centers enhance critical current density (Jc) value of these HTSC samples.

Bulk samples of (Sn1−xSbxO2−delta)(Sn_{1-x}Sb_{x}O_{2-\delta})(Sn1−xSbxO2−delta) with x = 0.00, 0.10, 0.20, 0.30 are synthesized by... more Bulk samples of (Sn1−xSbxO2−delta)(Sn_{1-x}Sb_{x}O_{2-\delta})(Sn1−xSbxO2−delta) with x = 0.00, 0.10, 0.20, 0.30 are synthesized by solid-state reaction route. Samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV-Vis spectroscopy. The x-ray diffraction patterns indicate that the gross structure/phase of (Sn1−x(Sn_{1-x}(Sn1−x SbxO2−delta)Sb_{x}O_{2-\delta})SbxO2−delta) do not change with the substitution of antimony (Sb) up to x = 0.30. The surface morphological examination with SEM revealed the fact that the grain size in the antimony doped sample is larger than that of undoped one and hence pores/voids between the grains increase with Sb concentration up to 0.30. TEM image of undoped sample indicates that the SnO2SnO_{2}SnO2 grains have diameters ranging from 25 to 120 nm and most grains are in cubic or spherical shape. As antimony content increases, the nanocubes/spheres are converted into microcubes/spheres. The reflectance of Sn1−xSbxO2−deltaSn_{1-x}Sb_{x}O_{2-\delta}Sn1−xSbxO2−delta samples increases whereas absorbance of these samples decreases with the increased concentration of antimony (Sb) for the wavelength range 360 - 800 nm. The energy bandgap of Sb doped - SnO2SnO_{2}SnO2 samples were obtained from optical absorption spectra by UV-Vis absorption spectroscopy. Upon increasing the Sb concentration the bandgap of the samples was found to increase from 3.367 eV to 3.558 eV.

Many of the general-relativity-tests such as bending of light near a star and gravitational red/b... more Many of the general-relativity-tests such as bending of light near a star and gravitational red/blue shift are explained without general-relativity & without Newtonian-approach. The authors first cast doubts on both, the Newtonian and the relativistic approach; and proposes a novel alternative-explanation. The new alternative explanation is based on refraction-phenomenon of optics. Estimation of results, with new approach, are in agreement with known values. Though physics is different, but it is argued that general-relativity based gravitational-bending and refraction-based bending have more in common than is generally realized. Also discussed are black-hole and gravitational-lensing in the new perspective of refraction. The new refraction-based theory makes a few new predictions and also suggests a few tests..

Integrated Ferroelectrics, 2011

Bulk superconductor samples of YBa2Cu3-xCoxO7-δ with x = 0, 0.01, 0.03, 0.05 are synthesized by s... more Bulk superconductor samples of YBa2Cu3-xCoxO7-δ with x = 0, 0.01, 0.03, 0.05 are synthesized by solid-state reaction route. Both x-ray diffraction and electron microscopy have been employed to study the phase identification, intergrowths, dislocations and the local structure of these samples. Transition temperature of the samples has been determined by four probe resistivity measurements. The x-ray diffraction patterns indicate that the gross structure/phase of YBa2Cu3-xCoxO7-δ do not change with the substitution of Co up to x = 0.05. The zero resistance critical transition temperature [Tc(R = 0)] is found to decrease and critical current density (Jc) increases with the increased concentration of cobalt in the compound. The Jc enhancement for the cobalt doped samples may be resulting due to flux pinning from some defects such as planar defects, stacking faults and micro defects (twin, domains etc.) and the rapid suppression in Tc may be due to the cooper pair breaking and the hole filling in the CuO2 planes.


`Zero-spin-photon hypothesis' as proposed in an earlier paper [1] states that: `due to inevitable... more `Zero-spin-photon hypothesis' as proposed in an earlier paper [1] states that: `due to inevitable consequence of the second-law of thermodynamics and spin-conservation, the `zero-spin-photon' is generated in pair-production process (of elementary particles), which decays into neutrino and antineutrino'. The zero-spin photon hypothesis explains [1] several riddles of physics and universe. In the present paper, it is shown that `the zero-spin photon hypothesis' when incorporated into the higer-order Feynman diagram (with a closed-loop) could possibly solve the half-a-century-old and famous `infinity-problem' of QED, and thus could avoid the need of the so called `re-normalization' procedure.


`What is work and what is heat' is re-investigated from the perspective of second law of thermody... more `What is work and what is heat' is re-investigated from the perspective of second law of thermodynamics. It is shown that the inevitable consequence of second law of thermodynamics and spin conservation necessitates the possible generation of zero spin photon in pair production process, and its subsequent decay explains the birth of neutrino and antineutrino. The proposed neutrino-genesis, solves many riddles of physics and universe. The riddles considered and explained are about: (i) mysterious neutrino (and antineutrino) and its bizarre properties such as handed-ness and parity-violation, (ii) questionable asymmetry/ excess of matter over antimatter, (iii) possibility of existence of antimatter world and (iv) parity (P) violation and aspects of CP and CPT violation or restoration in the universe.

In the present paper a new concept is introduced that: `mass is a complex quantity'. The concept ... more In the present paper a new concept is introduced that: `mass is a complex quantity'. The concept of complex-mass suggests that the total mass M of a moving body is complex sum of: (i) the real-part (grain or rest) mass mgm_{g}mg establishing its particle behaviour and (ii) the imaginary-part mass mpm_{p}mp governing its wave properties. Mathematically, the complex mass M=mg+impM = m_{g} + im_{p}M=mg+imp; the magnitude $\mid M \mid = (m_{g}^{2} + m_{p}^{2})^{{1/2}}. The theory proposed here explains successfully several effects such as `Compton effect' and `refraction of light' which could not be explained otherwise by a single theory of wave or particle. Also explained are `Doppler effect for light', `photo-electric effect', `Uncertainty principle', `Relativity' and `supersymmetry'