Strain induced magnetic domain evolution and spin re-orientation transition in epitaxial manganite films

The evolution of magnetic domain structure in epitaxial La$_{0.625}$Ca$_{0.375}$MnO$_3$ films on (001) NdGaO$_3$ is monitored as a function of temperature and magnetic field using Magnetic Force Microscopy. We see two distinct regions of magnetic orientational order; one in-plane displaying contrast-less image and the other tilted away from the film plane forming a distinct stripe pattern. A strong domain splitting is observed at the boundary of two regions, which is resilient to reorientation with temperature and magnetic field. We propose a model magnetic free energy functional to explain the mechanism of domain splitting seen in manganite films

Use of ICT tools (Tablet PC) to promote innovative teaching & learning and to develop students' 21st century skills at O' level: An action research case study in Mauritius

This paper outlines an action research case study in Mauritius to obtain crucial practitioner insights into the implementation of a Tablet PC project in a State Secondary School (National College) with O'level students, to promote innovative teaching & learning and to develop students' 21st century skills. The research was conducted over four weeks in a French literature class of 32 students when Tablet PC's were used to enhance and innovate their engagement with a satirical comedy play. Questionnaires and feedback forms were used to collect data from the students' perspective, in addition to teacher observations. This study investigates the general attitude of students about using information and communication technologies (ICT) tools such as Tablet PC and specialist softwares, as well as the impact on teaching and learning. It found that despite many limitations in the practicalities of using Tablet PC in schools, this ICT tool positively influenced student's learning behaviour, effective teaching & learning, and helped students develop 21st century skills

Electronic reconstruction and enhanced superconductivity at La1.6−x_{1.6-x}Nd0.4_{0.4}Srx_{x}CuO4_{4}/La1.55_{1.55}Sr0.45_{0.45}CuO4_{4} bilayer interface

We report enhanced superconductivity in bilayer thin films consisting of superconducting La$_{1.6-x}$Nd$_{0.4}$Sr$_{x}$CuO$_{4}$ with 0.06 $\leq x<$ 0.20 and metallic but non-superconducting La$_{1.55}$Sr$_{0.45}$CuO$_{4}$. These bilayers show a maximum increase in superconducting transition temperature ($T_c$) of more than 200% for $x$ = 0.06 while no change in $T_c$ is observed for the bilayers with $x\geq$ 0.20. The analysis of the critical current and kinetic inductance data suggests 2-3 unit cells thick interfacial layer electronically perturbed to have a higher $T_c$. A simple charge transfer model with cation intermixing explains the observed $T_c$ in bilayers. Still the unusually large thickness of interfacial superconducting layers can not be explained in terms of this model. We believe the stripe relaxation as well as the proximity effect also influence the superconductivity of the interface

Changes in the electronic structure and properties of graphene induced by molecular charge-transfer

Interaction with electron donor and acceptor molecules such as aniline and nitrobenzene brings about marked changes in the Raman spectrum and the electronic structure of graphene, prepared by the exfoliation of graphitic oxide.Comment: 13 pages, 4 figure

Interface superconductivity in La1.48_{1.48}Nd0.4_{0.4}Sr0.12_{0.12}CuO4_{4}/La1.84_{1.84}Sr0.16_{0.16}CuO4_{4} bilayers

We identify a distinct superconducting phase at the interface of a La$_{1.48}$Nd$_{0.4}$Sr$_{0.12}$CuO$_4$ (LNSCO)/La$_{1.84}$Sr$_{0.16}$CuO$_4$ (LSCO) epitaxial bilayer system using ac screening measurements. A model based on inter-diffusion of quasiparticles and condensate at the interface yields a thickness of $\sim$ 25 nm for the interfacial layer. Two-dimensional superconductivity of the interface layer appears to be governed by Kosterlitz-Thouless-Berezinskii transition. A parallel magnetic field suppresses the superconducting transition temperature of this layer with a pair breaking parameter $\alpha$ varying as $H^2$

Structure and Rheology of the Defect-gel States of Pure and Particle-dispersed Lyotropic Lamellar Phases

We present important new results from light-microscopy and rheometry on a moderately concentrated lyotropic smectic, with and without particulate additives. Shear-treatment aligns the phase rapidly, except for a striking network of oily-streak defects, which anneals out much more slowly. If spherical particles several microns in diameter are dispersed in the lamellar medium, part of the defect network persists under shear-treatment, its nodes anchored on the particles. The sample as prepared has substantial storage and loss moduli, both of which decrease steadily under shear-treatment. Adding particles enhances the moduli and retards their decay under shear. The data for the frequency-dependent storage modulus after various durations of shear-treatment can be scaled to collapse onto a single curve. The elasticity and dissipation in these samples thus arises mainly from the defect network, not directly from the smectic elasticity and hydrodynamics.Comment: 19 pages inclusive of 12 PostScript figures, uses revtex, psfrag and epsfig. Revised version, accepted for publication in Euro. Phys. J. B, with improved images of defect structure and theoretical estimates of network elasticity and scalin

Analysis of genetic relationships in cashew varieties using morphological characters and ISSR markers

In the present paper genetic relationships of twenty five varieties of cashew are described on the basis of morphological characters and ISSR markers. Results obtained for the phenotypic characters based on similarity coefficient were divided into four clusters with 70 per cent similarity. By means of similarity coefficients (SG), at 70 per cent phenon level the genotypes were broadly grouped into four clusters i.e., cluster I and cluster II both comprising of a single variety Bhaskara and Chintamani-1 respectively, cluster III having six varieties and cluster IV with 17 varieties. The analysis using ISSR markers allowed us to distinguish 25 varieties. A total of 81 distinct DNA fragments ranging from 0.1 to 2.5 kb were amplified by using 10 selected ISSR primers. Genetic similarity analysis was conducted for the presence or absence of bands in the ISSR profile. Cluster analysis clearly showed that 25 varieties of cashew could be grouped into two major clusters based on similarity indices. The first major cluster consists of Priyanka and Madakkathara-1, two moderate yielding varieties. The other major cluster was divided into two sub-minor clusters, one sub-minor cluster having single variety and the other sub-minor cluster was represented by 22 varieties. Among the 25 varieties, Kanaka and Vridhachalam-3 showed the highest similarity indices (92%). The analysis of genetic relationships in cashew using morphological traits and ISSR banding data can be useful for plant improvement, descriptions of new varieties and also for assessment of varietal purity in plant certification programmes