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Nano films of polytetrafluoroethylene (PTFE; commercially coded as Teflon) shows advantage over inorganic spacer materials like Al2O3 and MgO in fabricating tunneling magneto resistive devices due to its relative dielectric constant and chemical inertness to provide a homogenous metal-organic interface. Pulsed electron deposition proves useful in fabricating such thin PTFE films (3-6 nm) for trilayer device such as Fe (100 nm)/ PTFE (3-6 nm) /Fe (100 nm) on Si (100). Characteristic magnetic hysteresis loops demonstrating the magnetic tunnel junctions were realized for a PTFE organic layer thickness >3 nm. The tunneling magnetoresistance measurement at room temperature shows a typical magneto resistive feature, increasing with increasing PTFE thickness.

Copper(II) hydrazine carboxylate monohydrate, Cu(N2H3COO)2·H2O and chromium (II, III) hydrazine carboxylate hydrates, Cu(N2H3COO)2·H2O and Cu(N2H3COO)2·3H2O have been prepared and characterised by chemical analysis, IR, visible spectra and magnetic measurements. Thermal analysis of the copper complex yields a mixture of copper metal and copper oxide. Chromium complexes on thermal decomposition yield Cr2O3as residue. Decomposition of chromium(HI) complex under hydrothermal conditions yield CrOOH, a precursor to CrO2.

X-ray absorption spectroscopy studies of the polycrystalline SrRu_0.5Mn_0.5O₃ have been performed at Ru, Mn-L_2,3 edges. The 2p → t_2g related peak at the Ru-L₂ edge is more intense than the Ru-L₃ edge and a shift of the 2p → e_g related peak by ~0.8 eV to higher energy than that of the Ru(iv) compound, SrRuO₃ is observed. In combination with a crystal field multiplet calculation approach, a possible anomalous change in the spectral features is explained based on the existence of a redox ionic pair involving Ru(iv)/Ru(v) ↔ Mn(iii)/Mn(iv).

High qualityAg-doped YBa2Cu3O7-x (YBCO) thin films have been grown by laser ablation on < ¯1012 > bare sapphire. This work demonstrates thatAg-doping can be used as very convenient means to realize good quality YBCO films on highly coveted sapphire substrates for microwave applications of highTc thin films.

Pure and Ru-doped Li[Mn2−xRux]O4(x=0.1and 0.25) spinel compounds are prepared by the high temperature solid-state reaction and characterized by X-ray diffraction (XRD), scanning electron microscopy, Brunauer, Emmett, and Teller surface area, density, IR, Raman spectroscopy, and X-ray absorption spectroscopy. XRD studies show single-phase compounds with the cubic spinel structure and a decrease in (Mn–O) and an increase in (Li–O) bond lengths on Ru doping. The electrochemical cycling behavior of Li[Mn2−xRux]O4is examined by galvanostatic cycling and cyclic voltammetry (CV). The CV shows that the Mn3+↔Mn4+couple lies in the range from ∼4.0to∼4.2Vand the spinel-to-double-hexagonal (S-DH) transition at ∼4.5Vin agreement with results in the literature. The Ru4+↔Ru5+redox couple operates at ∼4.3Vvs Li in the spinel structure. The S-DH phase transition is suppressed on Ru doping. Charge–discharge cycling, up to 25 or 40cycles, in the voltage ranges 3.5–4.3 and 3.5–4.6Vvs Li at 0.14C rate gave initial charge capacities ranging from 118to139mAhg−1for various x. Compositions with x=0.1and 0.25 showed smaller initial capacity loss and smaller capacity fading during cycling as compared to x=0. For x=0.25in the voltage range 3.5–4.6Vand 2–25cycles, the capacity fade is only 9% thereby showing the beneficial effect of Ru doping, by way of suppression of S-DH transition, participation of Ru-redox couple, and better electronic conductivity of the compound during cycling, in comparison to pure LiMn2O4.

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