Effect of Electron Beam Irradiation on Structural, Electrical and Thermo-electric Power of La0.8Sr0.2MnO3

In this communication, we are reporting the effect of electron beam (e-beam) irradiation on thermoelectric properties of La0.8Sr0.2MnO3 manganites. The samples were prepared using solid state reaction technique. It is observed that the lattice volume increases with increase in dosage of e-beam. With irradiation an increase in resistivity is observed. For small irradiation dosage, we first observe a decreases in metalinsulator transition temperature TMI; thereafter TMI increases with further increase in dosage of irradiation. Both, the resistivity data and thermo-electric power data demonstrate that small polaron hopping model is valid in high temperature region

Effect of Electron Beam Irradiation on Structural, Electrical and Thermo-electric Power of La0.8Sr0.2MnO3

In this communication, we are reporting the effect of electron beam (e-beam) irradiation on thermoelectric properties of La0.8Sr0.2MnO3 manganites. The samples were prepared using solid state reaction technique. It is observed that the lattice volume increases with increase in dosage of e-beam. With irradiation an increase in resistivity is observed. For small irradiation dosage, we first observe a decreases in metalinsulator transition temperature TMI; thereafter TMI increases with further increase in dosage of irradiation. Both, the resistivity data and thermo-electric power data demonstrate that small polaron hopping model is valid in high temperature region

Investigation of Electrical and Thermoelectric Properties of ZnO/rGO Composites Prepared by Conventional Solid-state Reaction Method

ZnO/rGO composites are prepared by the conventional solid-state reaction method. Structural properties of prepared compounds were studied using XRD technique and it is observed that all the samples are crystallized in wurtzite structure. Electrical resistivity measurements were carried out using four probe method employing a closed cycle refrigerator. With addition of rGO, colossal reduction in the resistivity is observed which is about three orders of magnitude smaller than that of the pure sample of ZnO. Room temperature Hall measurements were performed to estimate the bulk concentration and results show that addition of rGO into ZnO matrix enhances the number of charge carriers. Thermopower measurements were carried out using differential dc method and a large reduction in Seebeck coefficient is observed

Surface superconducting states and paramagnetism in mesoscopic superconductors

In the framework of the Ginzburg-Landau equation, the temperature dependence of the upper critical field of small ring-like superconductors is studied. At equilibrium small parts of the phase diagram show paramagnetism for width / radius ratios below 0.85. Their number and extension increase with the size of the hole. In these regions, only the inner part of the ring shows a positive magnetic moment. The order parameter density profile appears to change, when crossing a first order transition line, which separates different angular momentum values, and we clarify the relationship between the localization of superconductivity nucleation and paramagnetism of those samples.Comment: 11 pages, 9 figure