Direct printing of functional oxide thin films could provide a new route to low-cost, efficient and scalable fabrications of electronic devices. One challenge that remains open is to design the inks with long term stability for effective deposition of specific oxide materials of industrial importance. In this paper, we introduce a reliable method of producing stable inks for ‘in-situ’ deposition of oxide thin films by inkjet printing. The inks were prepared from metal-acetates solutions and printed on a variety of substrates. The acetate precursors were decomposed into oxide films during the subsequent calcination process to achieve the ‘in-situ’ deposition of the desired oxide films directly on the substrate. By this procedure we have obtained room temperature contamination free ferromagnetic spintronic materials like Fe doped MgO and ZnO films from their acetate(s) solutions. We find that the origin of magnetism in ZnO, MgO and their Fe-doped films to be intrinsic. For a 28 nm thick film of Fe-doped ZnO we observe an enhanced magnetic moment of 16.0 emu/cm3 while it is 5.5 emu/cm3 for the doped MgO film of single pass printed. The origin of magnetism is attributed to cat-ion vacancies. We have also fabricated highly transparent indium tin oxide films with a transparency >95% both in the visible and IR range which is rather unique compared to films grown by any other technique. The films have a nano-porous structure, an added bonus from inkjetting that makes such films advantageous for a broad range of applications.

Ink-jet printing technique is used to prepare porous (ZnO)1−x(TiO2)x composite films on indium tin oxide-coated glass substrates. Dye-sensitized solar cells were fabricated using well-characterized printed films of thickness ∼20 and 30 μm, respectively. It is found that the photovoltaic performance of the cells is dependent on the film thickness and the concentrations of ZnO. The obtained results are compared with those of pure ZnO- and TiO2-based cells prepared by the same route to optimize the device efficiency. This study suggests that ink-jet printers promise an inexpensive and simple technology for manufacturing solar cell composite films.

The resistance or susceptibility of sorghum genotypes to damage by the spotted stemborer Chilo partellus (Swinhoe) is commonly measured in terms of leaf damage, deadheart formation and stem tunnelling. Effect of the host plant on the insect survival and development (antibiosis) and the response of the plant to insect damage (tolerance or recovery resistance) are also important parameters for measuring host plant resistance to stemborers. We compared ten selection indices commonly used to select genotypes for tolerance/resistance to various stresses, namely functional plant loss index (FPLI), antibiosis index (ABI), mean productivity index (MPI), mean relative performance (MRP), relative efficiency index (REI), tolerance index (TOL), Fischer's and Maurer's stress susceptibility index (FMSSI), Fernandez stress tolerance index (FSTI), geometric mean productivity (GMP) and Schneider's stress severity index (SSSI). The results suggest that the indices based on grain yield reduction can be combined with those associated with grain yield response and potential under borer-infested and uninfested conditions, since each index assesses different biological mechanisms (such as tolerance, adaptation and/or productivity). Among these, FPLI can be used to differentiate the sorghum genotypes for different components of resistance by taking into account both foliar damage and deadheart formation. GMP, REI and FSTI provided a better discrimination of the stemborer-tolerant genotypes under borer-infested conditions, and were better predictors of grain yield performance than TOL, MPI, MRP, ABI, SSSI, FMSSI and FPLI. A strong association between GMP and REI indicated that both these indices could be used to select for low grain yield loss and high productivity. However, the selection of genotypes with high grain yield potential and adaptation to borer infestation may be achieved by combining selection indices related to the mean grain yield performance under borer-infested and uninfested conditions (GMP and REI), and low levels of grain yield loss under borer infestation.

Printing of functional materials requires reliable deposition processes. This work describes the development of printing processes for selected functional materials utilizing industrial-type inkjet printheads. A well-controlled printing process with fluids containing the conductive polymer poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) is presented, allowing linear printing speeds of up to 0.35 m/s in single-pass, and smallest line width of approximately 40 μm when printing 7 pL drop volumes. In addition reliable processes for producing ZnO-based films, which enable novel applications for electronic and UV-sensitive devices, and for printing of conductive carbon nanotube layers are shown.

A single specimen of paper bubble shell, Hydatina zonata was collected in trawl catches at a depth of 30 m off Koyyam, Bay of Bengal. A literature review on the distribution of this species revealed that this is the first report of H. zonata from the north-east coast of India. A note on the morphological features of this specimen is detailed in this paper.

The wurtzite polymorph of GaN was calcined with CuO in flowing nitrogen. As a result of this processing, both superconducting quantum interference device magnetometry and ferromagnetic resonance studies showed ferromagnetism in these samples at room temperature. These magnetic results are qualitatively consistent with very recent first-principle calculations [Wu et al., Appl. Phys. Lett.89, 062505 (2006)] that predict ferromagnetism in Cu-doped GaN. We focus in this paper on analyzing changes in the GaN atomic and electronic structure due to calcination with CuO using multiple analytical methods. Quantitative powder x-ray diffraction (XRD) showed changes in the lattice constants of the GaN due to the incorporation of copper (and possibly oxygen). Energy-dispersive x-ray spectroscopy proved the incorporation of copper into the GaN crystal structure. Electron-gun monochromated electron energy loss spectroscopy showed CuO calcinations-induced GaN band gap changes and indicated changes in the atomic arrangements due to the calcination process. The fine structure of the N K-edge showed differences in the peak ratios with respect to higher nominal CuO contents, corresponding to an increase in the c-lattice constant as confirmed by XRD.

Gallium nitride powders and zinc oxide powders were each calcined with a few weight percent of copper oxide and/or magnesium oxide either in air or N2. Powder X-ray diffractometry, transmission electron microscopy, energy dispersive X-ray spectroscopy, and electron energy loss spectroscopy were performed in order to observe calcination induced structural effects on these wurtzite type semiconductors. We note that our earlier magnetic results on Cu doped GaN are qualitatively consistent with recent first principle calculations [Wu et al., Appl. Phys. Lett. 89 (2006) 62505].

Ferrofluids containing superparamagnetic Fe3O4 nanoparticles have been prepared by a controlled co-precipitation method.The aggregation of the particles was prevented by using a polymeric starch network as a coating agent. Structural and magnetic measurements reveal a particle size of around 6 nm, with a clear evidence of a uniform particle coating. The ferrofluids have been used as a contrast agent for MR imaging in biological tissue.

The magnetic properties of novel bulk glassy Nd60Fe30Al10 magnets around the transition to the paramagnetic state have been studied in order to understand the magnetic microstructure in these materials. Analyses of the critical behavior of the magnetic isotherms suggest a transition from a low field magnetic state to a ferromagnetic-like state upon the application of high enough magnetic fields. The ferromagnetic-like state is evidenced by a scaling of the magnetization curves with critical exponents λ=1.5(1), β=0.65(5), and TC=465 K. These results are consistent with the predictions for weak random magnetic anisotropy systems.

The large values over 300 kA/m at room temperature were found for the coercive field of Nd50Fe40Si10−xAlx (x = 0; 10) amorphous melt-spun ribbons and cast rods. The dependence of the coercive field on the thickness and the preparation method, namely the cooling rate, is ascribed to the existence in the amorphous matrix of very small ferromagnetic clusters, which approach of a single magnetic domain. Coercivity increases substantially up to 600 kA/m by decreasing the temperature down to 200 K, although the measurements are carried out in low fields (up to 800 kA/m). The Mässbauer spectra can be fitted to two Fe sites with magnetic moments ranging from 1.25 to 2.20νB depending on the additional element.

Controlled microstructured thin films with nominal composition Cu95Co5 have been deposited on glass substrates by pulsed laser ablation at room temperature, in vacuum, for different target speed rotation. Atomic Force Microscopy, AFM, studies have shown a surface roughness not higher than 0.5 nm, for the as-deposited samples, which do not exhibit magnetoresistive, MR, behaviour. X-ray diffraction analysis show broad diffraction peaks, slightly shifted from pure Cu reflection peaks. After annealing, the samples show GMR. The AFM investigations reveal a surface roughness of =6.8 nm and =9.2 nm for the samples prepared with high and low target speed rotation, respectively. Furthermore the GMR data correspond to a strong anisotropic behaviour. A reversible MR is exhibited, for all the films, exclusively for perpendicular to the films plane applied magnetic field. Hysteretic MR behaviour is observed for any other direction: in the range of 70-80 deg., coercive MR fields from 0.17 Tesla to 0.05 Tesla are observed for the samples obtained at 10 rpm to 32 rpm respectively target speed rotation. These properties are discussed in terms of the shape anisotropy of magnetic Co nanoparticles.

Submicron thick Bi, Ga substituted dysprosium iron garnet films were laser deposited on Gd3Ga5O12(GGG) and ceramic glass substrates at room temperature and then post annealed by rapid thermal annealing (RTA). From Faraday rotation studies, the films deposited on glass substrates are found to exhibit perpendicular magnetic anisotropy, Faraday rotation of 0.88 deg / μm, and coercive field Hc of 0.88 kOe. On the other hand, films deposited on GGG substrates with the same processing parameters are found to exhibit perpendicular anisotropy, but with much smaller values for Faraday rotation(0.03 deg; μm) and coercive field Hc(0.018 kOe). The uniaxial magnetic anisotropy with easy magnetization axis perpendicular to the film surface is caused by the stress induced on the polycrystalline film / substrate interface. The effect of changing the oxygen pressures, in the range of 20 to 100 mTorr during the deposition process, on the crystalline structure as well as coercive field and Faraday rotation angle are also presented.

We propose an angular redistribution model to understand the negative ions resputtering effect in sputter depositing YBa2Cu3O7−x (YBCO) films. On the basis of this model, the negative oxygen ions resputtering effect has been greatly minimized by introducing a Cu mask between the substrate and the target to block energetic oxygen particles from directly bombarding the growing film. Thus, YBCO films with almost exact stoichiometric composition and zero resistance critical temperatures as high as 90 K are obtained under oxygen partial pressure as low as 3 mTorr in a temperature regime well beyond that proposed by R.H. Hammond and R. Bormann. Preliminary results of a modified masking and shiclding technique to eliminate the resputtering effect and fabricate large area (>1 in. × 1 in.) YBCO superconducting films with high uniformity are also presented.

Studies of the evolution of electrical resistance in an external applied magnetic field, B, as well as with temperature, T, on Cu86Co14 and Cu92Co8 as quenched and annealed melt-spun ribbons, reveal that magnetoresistance, MR, ΔR(B,T)=R(B)-R(0) scales with B/T. Furthermore, it found that annealing up to 600 °C scales the magnetic moment of the Co-rich superparamagnetic nanoparticles such that, the data for the field dependence of the MR obtained at various temperatures collapses onto the same unique and universal curve f(mB/T) with the Langevin variable mB/T governing the overall behaviour.

Low field (∿5 Oe)Magneto-Thermo-Gravimetric technique has been used to study the effects of substitution of Nd with Y, Gd, and Dy in melt-spun Fe77Nd15B8 alloys, and also to monitor the changes in the magnetic properties on heat treatment to achieve optimum magnetic hardening in these alloys. From VSM-measurements preliminary studies of the effect of substitution for Nd on the hysteretic loops are presented.

In the system (FeXNi1−x)75P16B6Al3 an unusual magnetic behaviour is found in the composition range 0.2<x<0.3. The drastic changes seen at low temperature in the thermomagnetic measurements is found not to affect the Mössbauer spectra. From the width of the magnetic hyperfine field distribution as function of temperature there seems to be a distribution in Curie temperatures. Due to the absence of spin texture it was not possible to make a distinction between the two proposed low temperature phases although the general results favour the spin glass alternative.