Negative Giant Longitudinal Magnetoresistance in NiMnSb/InSb: An interface effect

We report on the electrical and magneto-transport properties of the contact formed between polycrystalline NiMnSb thin films grown using pulsed laser deposition (PLD) and n-type degenerate InSb (100) substrates. A negative giant magnetoresistance (GMR) effect is observed when the external magnetic field is parallel to the surface of the film and to the current direction. We attribute the observed phenomenon to magnetic precipitates formed during the magnetic film deposition and confined to a narrow layer at the interface. The effect of these precipitates on the magnetoresistance depends on the thermal processing of the system.Comment: 14 pages, 4 figure

Surface and interface study of pulsed-laser-deposited off-stoichiometric NiMnSb thin films on Si(100) substrate

We report a detailed study of surface and interface properties of pulsed-laser deposited NiMnSb films on Si (100) substrate as a function of film thickness. As the thickness of films is reduced below 35 nm formation of a porous layer is observed. Porosity in this layer increases with decrease in NiMnSb film thickness. These morphological changes of the ultra thin films are reflected in the interesting transport and magnetic properties of these films. On the other hand, there are no influences of compositional in-homogeneity and surface/interface roughness on the magnetic and transport properties of the films.Comment: 13 pages, 7 figures, Submitted to Phys. Rev.

X-ray standing wave and reflectometric characterization of multilayer structures

Microstructural characterization of synthetic periodic multilayers by x-ray standing waves have been presented. It has been shown that the analysis of multilayers by combined x-ray reflectometry (XRR) and x-ray standing wave (XSW) techniques can overcome the deficiencies of the individual techniques in microstructural analysis. While interface roughnesses are more accurately determined by the XRR technique, layer composition is more accurately determined by the XSW technique where an element is directly identified by its characteristic emission. These aspects have been explained with an example of a 20 period Pt/C multilayer. The composition of the C-layers due to Pt dissolution in the C-layers, Pt$_{x}$C$_{1-x}$, has been determined by the XSW technique. In the XSW analysis when the whole amount of Pt present in the C-layers is assumed to be within the broadened interface, it l eads to larger interface roughness values, inconsistent with those determined by the XRR technique. Constraining the interface roughness values to those determined by the XRR technique, requires an additional amount of dissolved Pt in the C-layers to expl ain the Pt fluorescence yield excited by the standing wave field. This analysis provides the average composition Pt$_{x}$C$_{1-x}$ of the C-layers .Comment: 12 pages RevTex, 10 eps figures embedde

Finitely presented left orderable monsters

A left orderable monster is a finitely generated left orderable group all of whose fixpoint-free actions on the line are proximal: the action is semiconjugate to a minimal action so that for every bounded interval $I$ and open interval $J$, there is a group element that sends $I$ into $J$. In his 2018 ICM address, Navas asked about the existence of left orderable monsters. By now there are several examples, all of which are finitely generated but not finitely presentable. We provide the first examples of left orderable monsters that are finitely presentable, and even of type $F_\infty$. The construction itself is elementary, and these groups satisfy several additional properties separating them from the previous examples: they are not simple, they act minimally on the circle, and they have an infinite-dimensional space of homogeneous quasimorphisms. Our construction is flexible enough that it produces infinitely many isomorphism classes of finitely presented (and type $F_{\infty}$) left orderable monsters.Comment: 12 pages. v2: Final version, to appear in Ergodic Theory and Dynamical System

PHOTOCATALYTICDEGRADATION OF RHODAMIN-B USING METAL COMPLEXES AND HYDROGEN PEROXIDE

ABSTRACT The photocatalytic degradation has been considered to be an efficient process for degradation of organic pollutants, which are present in the effluents released by industries. Thephotocatalytic bleaching was carried out on rhodamin-B (cationic dye) in the presence of iron (III) complex, hydrogen peroxide and was observed spectrophotometrically. The effect of various operating variables like pH, concentration of complex and dye, amount of HzOzand light intensity etc. was also observed on the efficiency of the reaction. A tentative mechanism has also been proposed for this photocatalytic degradation of rhodamin-B. Keywords: Photocatalytic degradation, rhodamin-B, metal complexes, hydrogen peroxide

Comparative efficacy of biological control agents for the management of cumin wilt caused by Fusarium oxysporum f.sp. cumini

Field experiments were conducted during rabi 2008-09 and 2009-10 for the management of cumin wilt caused by Fusarium oxysporum f.sp. cumini. The results showed that seed treatment with Trichoderma viride (10 g kg-1 of seed) and soil application (2.5 kg ha-1) recorded minimum percent disease incidence (PDI) of 18.5 (disease reduction of 51.8%) versus 38.4 in the control. It was on par with seed treatment and soil application with Aspergillus versicolor at 10 g kg-1 of seed and 2.5 kg ha-1, respectively which reduced the disease incidence by 45.4%. The chemical treatment i.e. seed treatment with carbendazim at 2.5 g kg-1 seed recorded PDI of 23.9 with 37.7% disease reduction. Among different treatments seed treatment and soil application with A. versicolor gave a seed yield of 246 kg ha-1 followed by P. fluorescens (222.6 kg ha-1). Treatment T. viride, recorded the highest yield of 258.2 kg ha-1. Hence, seed treatment at 10 g kg-1 and soil application at 2.5 kg ha-1 of T. viride was the most effective, eco-friendly disease management. &nbsp

Comparative efficacy of biological control agents for the management of cumin wilt caused by Fusarium oxysporum f.sp. cumini

Field experiments were conducted during rabi 2008-09 and 2009-10 for the management of cumin wilt caused by Fusarium oxysporum f.sp. cumini. The results showed that seed treatment with Trichoderma viride (10 g kg-1 of seed) and soil application (2.5 kg ha-1) recorded minimum percent disease incidence (PDI) of 18.5 (disease reduction of 51.8%) versus 38.4 in the control. It was on par with seed treatment and soil application with Aspergillus versicolor at 10 g kg-1 of seed and 2.5 kg ha-1, respectively which reduced the disease incidence by 45.4%. The chemical treatment i.e. seed treatment with carbendazim at 2.5 g kg-1 seed recorded PDI of 23.9 with 37.7% disease reduction. Among different treatments seed treatment and soil application with A. versicolor gave a seed yield of 246 kg ha-1 followed by P. fluorescens (222.6 kg ha-1). Treatment T. viride, recorded the highest yield of 258.2 kg ha-1. Hence, seed treatment at 10 g kg-1 and soil application at 2.5 kg ha-1 of T. viride was the most effective, eco-friendly disease management. &nbsp

Pleosporales

One hundred and five generic types of Pleosporales are described and illustrated. A brief introduction and detailed history with short notes on morphology, molecular phylogeny as well as a general conclusion of each genus are provided. For those genera where the type or a representative specimen is unavailable, a brief note is given. Altogether 174 genera of Pleosporales are treated. Phaeotrichaceae as well as Kriegeriella, Zeuctomorpha and Muroia are excluded from Pleosporales. Based on the multigene phylogenetic analysis, the suborder Massarineae is emended to accommodate five families, viz. Lentitheciaceae, Massarinaceae, Montagnulaceae, Morosphaeriaceae and Trematosphaeriaceae