Multi-environment Analysis for Indian Sites

GENOTYPE-BY-ENVIRONMENT interactions (GEI) are ubiquitous for quantitative traits of economic importance. Significant GEI tends to hinder genetic progress in a breeding program; in particular, the crossover type of GEI makes it difficult to unambiguously select promising materials that perform consistently better across a wide range of environmental conditions. The first step to deal with the consequences of the presence of GEI is to assess its relative importance through a pooled analysis of data across the testing sites

Homochiral antiferromagnetic merons, antimerons and bimerons realized in synthetic antiferromagnets

The ever-growing demand for device miniaturization and energy efficiency in data storage and computing technology has prompted a shift towards antiferromagnetic (AFM) topological spin textures as information carriers, owing to their negligible stray fields, leading to possible high device density and potentially ultrafast dynamics. We realize, in this work, such chiral in-plane (IP) topological antiferromagnetic spin textures, namely merons, antimerons, and bimerons in synthetic antiferromagnets by concurrently engineering the effective perpendicular magnetic anisotropy, the interlayer exchange coupling, and the magnetic compensation ratio. We demonstrate by three-dimensional vector imaging of the N\'eel order parameter, the topology of those spin textures and reveal globally a well-defined chirality, which is a crucial requirement for controlled current-induced dynamics. Our analysis reveals that the interplay between interlayer exchange and interlayer magnetic dipolar interactions plays a key role in significantly reducing the critical strength of the Dzyaloshinskii-Moriya interaction required to stabilize topological spin textures, such as AFM merons, making synthetic antiferromagnets a promising platform for next-generation spintronics applications.Comment: 18pages, 5 figure

Lattice-Match Stabilization and Magnetic Properties of Metastable Epitaxial Permalloy-Disilicide Nanostructures on a Vicinal Si(111) Substrate

We report the epitaxial formation of metastable γ-(FexNi1−x)Si2 nanostructure arrays resulting from the reaction of Ni80Fe20 permalloy with vicinal Si(111) surface atoms. We then explore the effect of structure and composition on the nanostructure’s magnetic properties. The low-temperature annealing (T < 600 °C) of a pre-deposited permalloy film led to solid-phase epitaxial nucleation of compact disk-shaped island nanostructures decorating <110> ledges of the stepped surface, with either (2 × 2) or (3×3) R30° reconstructed flat top faces. High resolution scanning transmission electron microscopy analysis demonstrated fully coherent epitaxy of the islands with respect to the substrate, consistent with a well-matched CaF2-prototype structure associated with γ-FeSi2, along perfect atomically sharp interfaces. Energy dispersive spectroscopy detected ternary composition of the islands, with Fe and Ni atoms confined to the islands, and no trace of segregation. Our magnetometry measurements revealed the superparamagnetic behavior of the silicide islands, with a blocking temperature around 30 K, reflecting the size, shape, and dilute arrangement of the islands in the assembly

Upper mantle anisotropy inferred from shear wave splitting beneath the Eastern Indian Shield region

We estimate the shear wave splitting parameters vis-à-vis the thicknesses of the continental lithosphere beneath the two permanent seismic broadband stations located at Dhanbad (DHN) and Bokaro (BOKR) in the Eastern Indian Shield region. Broadband seismic data of 146 and 131 teleseismic earthquake events recorded at DHN and BOKR stations during 2007–2014 were analyzed for the present measurements. The study is carried out using rotation-correlation and transverse component minimization methods. We retain our “Good”, “Fair” and “Null” measurements, and estimate the splitting parameters using 13 “Good” results for DHN and 10 “Good” results for BOKR stations. The average splitting parameters (ϕ, δt) for DHN and BOKR stations are found to be 50.76°±5.46° and 0.82 ± 0.2 s and 56.30°±5.07° and 0.95 ± 0.17 s, and the estimated average thicknesses of the anisotropic layers beneath these two stations are ∼ 94 and ∼109 km, respectively. The measured deviation of azimuth of the fast axis direction (ϕ) from the absolute motion of the Indian plate ranges from ∼8° to 14°. The measured deviation of azimuth of the fast axis direction (ϕ) from the absolute motion of the Indian plate ranges from ∼8° to 14°. The eastward deviation of the fast axis azimuths from absolute plate motion direction is interpreted to be caused by induced outflow from the asthenosphere. Further, the delay time found in the present analysis is close to the global average for continental shield areas, and also coherent with other studies for Indian shield regions. The five “Null” results and the lower delay time of ∼0.5–0.6 s might be indicating multilayer anisotropy existing in the mantle lithosphere beneath the study area. Keywords: Eastern Indian shield, Seismic anisotropy, Splitting parameters, Absolute plate motio

Understanding self ion damage in FCC Ni-Cr-Fe based alloy using X-ray diffraction techniques

Using X-ray diffraction line profile analysis (XRDLPA) approach the radiation response of FCC Ni-Cr-Fe based alloy 690 to 1.5 and 3 MeV Ni2+ ion damage was quantified in terms of its microstructural parameters. These microstructural parameters viz. average domain size, microstrain and dislocation density were found to vary anisotropically with fluence. The anisotropic behaviour is mainly attributable to presence of twins in pre-irradiated microstructure. After irradiation, surface roughness increases as a function of fluence attributable to change in surface and sub-surface morphology caused by displacement cascade, defects and sputtered atoms created by incident energetic ion. The radiation hardening in case of 1.5 MeV Ni2+ irradiated specimens too is a consequence of the increase in dislocation density formed by interaction of radiation induced defects with pre-existing dislocations. At highest fluence there is an initiation of saturation. (C) 2018 Elsevier B.V. All rights reserved