Bulk samples of \((Sn_{1-x}Sb_{x}O_{2-\delta})\) 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 \((Sn_{1-x}\) \(Sb_{x}O_{2-\delta})\) 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 \(SnO_{2}\) 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 \(Sn_{1-x}Sb_{x}O_{2-\delta}\) 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 - \(SnO_{2}\) 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.
The magnetization as a function of magnetic field showed hysteretic behavior at room temperature. According to the temperature dependence of the magnetization, the Curie temperature \((T_{C})\) is ...higher than 350 K. Ferromagnetic Mn-doped tin oxide thin films exhibited low electrical resistivity and high optical transmittance in the visible region (400-800 nm). The coexistence of ferromagnetism, high visible transparency and high electrical conductivity in the Mn-doped \(SnO_{2}\) films is expected to be a desirable trait for spintronics devices.
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.
The structural, optical and electrical properties of spray deposited antimony (Sb) doped tin oxide (SnO2) thin films, prepared from SnCl4 precursor, have been studied as a function of antimony doping ...concentration. The doping concentration was varied from 0 to 1.5 wt.% of Sb. The analysis of x-ray diffraction patterns revealed that the as deposited doped and undoped tin oxide thin films are pure crystalline tetragonal rutile phase of tin oxide which belongs to the space group P42/mnm (number 136). The surface morphological examination with field emission scanning electron microscopy (FESEM) revealed the fact that the grains are closely packed and pores/voids between the grains are very few. The transmittance spectra for as-deposited films were recorded in the wavelength range of 200 to 1000 nm. The transmittance of the films was observed to increase from 57% to 68% (at 800 nm) on initial addition of Sb (up to Sb/Sn = 0.5 wt.%) and then it is decreased for higher level of antimony doping (Sb/Sn > 0.5 wt.%). The sheet resistance of tin oxide films was found to decrease from 48 \Omega/sq for undoped films to 8 \Omega/sq for antimony doped films.
Bulk superconductor samples of YBa2Cu3-xCoxO7-{\delta} 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-{\delta} 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 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 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.
`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.
