Resistivity of Fe/Al Multilayered Thin Films from Low Temperature to Room Temperature

By using electron beam gun and thermal deposition techniques in the vacuum range 6 x10-5mbar. The pure materials of 99.99% purity of iron and aluminium multilayers films grown on glass substrates at 300K in the following viz. The resistance was measured using four probe method at UGC-DAE Consortium Indore (4.2K to 300K) later resistivity, conductivity, temperature co-efficient of resistance (TCR), residual resistivity ratio (RRR) , and activation energy(Ea) were calculated. The resistivity behavior shown that the resistivity is increased with increasing the n value, resistivity is increased with increasing temperature. The data belonging to metallic region has been analyzed using the conventional power law’s and it is first time this set of films have explore resistivity at low temperature.

Fabrication and thermoelectric properties of n-type (Sr0.9Gd0.1)TiO3 oxides

The n-type oxides ( Sr 0.9 Gd 0.1) TiO 3 (SGTO) have been successfully prepared via a sol–gel process followed by solid-state sintering. The effects of sintering temperature on the thermoelectric (TE) properties of the SGTO samples have been investigated. The Seebeck coefficient showed no obvious difference, while the electrical conductivity increased with increasing sintering temperature, benefiting from an enhancement of densification. The maximum power factor (PF) value, ~ 20.5μW/K2cm at 370 K in the metallic region, was observed for the sample sintered at 1748 K. As a result, the peak figure of merit (ZT) values for the samples sintered at higher than 1673 K were in the range of 0.28–0.30. All the results indicate that such synthetic method provides a simple and effective way to prepare TE oxides.

Effects of Ag Nanocubes with Different Corner Shape on the Absorption Enhancement in Organic Solar Cells

The effects of corner shape of silver (Ag) nanocubes (NCs) on optical absorptions of organic solar cells (OSCs) are theoretically investigated by finite element method (FEM) calculations. The absorption of sun light in the active layer is calculated. Significant absorption enhancements have been demonstrated in metallic region with different shapes of Ag NCs, among them corner radius (R) is zero result in the best light absorption performance of up to 55% enhancement with respect to bare OSCs. The origins of increased absorption are believed to be the effects of the huge electric field enhancement and increased scattering upon the excitation of localized surface plasmon resonance (LSPR). Apart from usingR=0, we show thatR=3, 6, and 11.29 of Ag NCs in metallic region of active layer may also result in the maximum comparable absorption enhancement of 49%, 41%, and 28%, respectively. In addition, a significant effect of the period of NCs is observed.

Structure – Transport Correlations in Mono-Valent Na+ Doped La1-xNaxMnO3 Manganites

We report the results of the structural, transport and magnetotransport studies on mono-valent doped La1-xNaxMnO3 (LNMO) (x = 0.05, 0.1 and 0.15) manganites. XRD measurement and Rietveld refinement on LNMO samples shows that, all the samples crystallize in distorted rhombohedral structure without any additional impurity peaks. The d.c. four probe resistivity measurements show that, the metal-insulator transition temperature (TP) exhibited by the Na doped manganites increases and resistivity decreases with increasing x. This behavior has been explained on the basis of size disorder effect, tolerance factor variation and structural modifications due to large size mono-valent Na-doping. In the metallic region, the resistivity data have been fitted to the zener double exchange (ZDE) polynomial law for all the three samples. Magnetoresistance (MR) studies show a decrease in low temperature (5K) MR while increase in room temperature MR with increase in Na-content in the LNMO manganites.

Article

Secondary ion mass spectrometry (SIMS) has been used to guide the search for an oxidation procedure that can produce a thin and relatively sharp oxide layer on macroscopic zirconium. A new preparation based on dip coating in H2O2 solution is indicated to be suitable for this purpose. SIMS further indicates that the oxide interface, for such a prepared sample, shows substantial degradation when it is heated in H2 gas at 300°C. The presence of H appears to facilitate O migration into the metallic region, an observation that supplements those made previously on oxidized thin-film samples of zirconium prepared by deposition under ultrahigh-vacuum conditions.Key words: secondary ion mass spectrometry, interfacial reactivity, oxidized zirconium.

Effect of Co3+ Ion on Metal-Insulator Transition in (La0.1Ca0.9)(Mn1-xCox)O3

Orthorhombic perovskite-type (La0.1Ca0.9)(Mn1-xCox)O3 was synthesized in the range 0.00 ≤ x ≤ 0.08. The Rietveld analysis indicates that the (Mn, Co)-O(1 and 2) distances are independent of the composition (x). Measurements of the electrical resistivity (ρ) and the Seebeck coefficient (α) indicate that (La0.1Ca0.9)(Mn1-xCox)O3 is an n-type semiconductor at the low temperature. At the high temperature, (La0.1Ca0.9)(Mn1-xCox)O3 exhibits a metal-insulator transition in the range 0.0 ≤ x ≤ 0.04. The metal-insulator transition temperature (Tt) increases with increasing the Co3+ ion content, while dρ/dT in the metallic region decreases with increasing the Co3+ ion content. The variation of Ea and T+ is explained by the difference in the electronegativity between Mn and Co atoms. The variation of dρ/dT in the metallic region is explained by the increase in the collective o bond.