Kartik Senapati
A5012937890- Physics of Superconductivity and Magnetism
- Magnetic properties of thin films
- Quantum and electron transport phenomena
- ZnO doping and properties
- Dark Matter and Cosmic Phenomena
- Rare-earth and actinide compounds
- Superconductivity in MgB2 and Alloys
- Magnetic and transport properties of perovskites and related materials
- Particle physics theoretical and experimental studies
- Superconducting Materials and Applications
- Particle Detector Development and Performance
- Theoretical and Computational Physics
- Iron-based superconductors research
- Electronic and Structural Properties of Oxides
- Surface and Thin Film Phenomena
- Advanced Condensed Matter Physics
- Gas Sensing Nanomaterials and Sensors
- GaN-based semiconductor devices and materials
- Magnetic Properties and Applications
- Metal and Thin Film Mechanics
- Cosmology and Gravitation Theories
- Ga2O3 and related materials
- Neutrino Physics Research
- Molecular Junctions and Nanostructures
- Crystallization and Solubility Studies
Homi Bhabha National Institute
2023-2024
National Institute of Science Education and Research
2015-2024
Center for Interdisciplinary Studies
2023
University of Cambridge
2008-2020
Southern Methodist University
2018
Mitchell Institute
2017
Texas A&M University
2017
Indian Institute of Technology Bhubaneswar
2017
Indian Institute of Technology Kanpur
2002-2010
We present the first limits on inelastic electron-scattering dark matter and photon absorption using a prototype SuperCDMS detector having charge resolution of 0.1 electron-hole pairs (CDMS HVeV, 0.93 g CDMS high-voltage device). These electron-recoil significantly improve experimental constraints particles with masses as low 1 MeV/c^{2}. demonstrate sensitivity to photons competitive other leading approaches but substantially less exposure (0.49 d). results scientific potential...
The SuperCDMS experiment is designed to directly detect weakly interacting massive particles (WIMPs) that may constitute the dark matter in our Galaxy. During its operation at Soudan Underground Laboratory, germanium detectors were run CDMSlite mode gather data sets with sensitivity specifically for WIMPs masses ${<}$10 GeV/$c^2$. In this mode, a higher detector-bias voltage applied amplify phonon signals produced by drifting charges. This paper presents studies of experimental noise and...
We report the result of a blinded search for Weakly Interacting Massive Particles (WIMPs) using majority SuperCDMS Soudan dataset. With an exposure 1690 kg days, single candidate event is observed, consistent with expected backgrounds. This analysis (combined previous Ge results) sets upper limit on spin-independent WIMP--nucleon cross section $1.4 \times 10^{-44}$ ($1.0 10^{-44}$) cm$^2$ at 46 GeV/$c^2$. These results set strongest limits WIMP--germanium-nucleus interactions masses $>$12
The Cryogenic Dark Matter Search low ionization threshold experiment (CDMSlite) searches for interactions between dark matter particles and germanium nuclei in cryogenic detectors. has achieved a energy with improved sensitivity to low-mass (<10 GeV/c$^2$) particles. We present an analysis of the final CDMSlite data set, taken different detector than was used two previous sets. This includes "salting" method protect against bias, noise discrimination, background modeling, use profile...
We present an analysis of electron recoils in cryogenic germanium detectors operated during the SuperCDMS Soudan experiment. The data are used to set new constraints on axioelectric coupling axionlike particles and kinetic mixing parameter dark photons, assuming respective species constitutes all galactic matter. This study covers mass range from $40\text{ }\text{ }\mathrm{eV}/{c}^{2}$ $500\text{ }\mathrm{keV}/{c}^{2}$ for both candidates, excluding previously untested space masses below...
Tunnel junctions incorporating GdN ferromagnetic semiconductor barriers show a spin polarization exceeding 90% and high conductance. These devices an unusual low-bias conductance peak arising from strong bias-dependence of the polarization. This originates magneto-electric coupling within double Schottky barrier formed with NbN electrodes. As service to our authors readers, this journal provides supporting information supplied by authors. Such materials are peer reviewed may be re-organized...
We report a study of the structure and magnetic behavior polycrystalline GdN films grown at room temperature by reactive magnetron sputtering. By controlling relative fraction species during film growth, we observe continuous crossover from soft ferromagnetic into relatively hard films. While samples with Curie (${T}_{c}$) less than $~60$ K showed low coercive fields, significant increase in hysteretic loss was observed for ${T}_{c}\ensuremath{\gtrsim}$ 60 K. Accompanying change films,...
Abstract Field-dependent resistance of a magnetic layer is often used as the basic tunable operational entity in several spintronics applications. In this work we demonstrate that magnetoresistance (MR) classic ferromagnetic Ni can be tuned significantly by controlling surface spin scattering electrons, manipulating disordered spins via proximity effect. This was achieved drop casting molecules well-known single molecule magnet Mn12-ac on micro-tracks thin (∼12 nm) film. We found significant...
We report the spontaneous formation of superconducting NiBi3 phase in thermally evaporated Ni-Bi bilayer films. High reaction-diffusion coefficient Bi is believed to drive during deposition on Ni film. Cross sectional transmission electron microscopy and glancing incidence X-ray depth profiling confirmed presence throughout top layer. Superconducting transition at ∼3.9 K, close bulk value, was by transport magnetization measurements. The bilayers were irradiated with varying fluence 100 MeV...
The normal-state transport and the dynamic vortex response in simple cubic (sc) face-centered (fcc) polymorphs of NbN synthesized as epitaxial films thickness ${d}_{F}\ensuremath{\sim}2000\phantom{\rule{0.3em}{0ex}}\mathrm{\AA{}}$ using technique pulsed laser ablation are reported. nonequilibrium sc phase stabilizes on (100) MgO at elevated deposition temperatures ${T}_{D}$ $(>200\phantom{\rule{0.2em}{0ex}}\ifmmode^\circ\else\textdegree\fi{}\mathrm{C})$, over a restricted range nitrogen...
We propose a mechanism responsible for the abrupt vanishing of dendritic flux instability found in many superconducting films when an increasing magnetic field is applied. The onset avalanches and subsequent reentrance stability NbN were investigated using magneto-optical imaging, threshold fields measured as functions critical current density ${j}_{c}$. results are explained with excellent quantitative agreement by thermomagnetic model published recently [D. V. Denisov et al., Phys. Rev. B...
Spin-singlet Cooper pairs convert to spin-triplet on passing through a magnetically noncollinear structure at superconductor(S)/ferromagnet(F) interface. In this context, the generation of triplet supercurrents intrinsic ferromagnetic domain walls, which are naturally occurring magnetic features, was proposed theoretically in past decade. However, an experimental demonstration has been lacking literature, particularly because difficulty accessing single wall, is typically buried between two...
Abstract We report the effect of nitrogen partial pressure on growth niobium-titanium nitride (NbTiN) thin films through reactive sputtering NbTi target in presence Ar and N 2 atmosphere. The was varied from 5.8% to 15.15% with respect flow available chamber. measured a critical temperature ( T C ) as high 15.77 K for an 6.8% 50 nm film deposited MgO substrate. epitaxial NbTiN is evident observed (200) (400) XRD peaks superconducting properties were analyzed values C, Δ dependence upper...
The issue of interlayer exchange coupling in magnetic multilayers with a superconducting spacer is addressed ${\mathrm{La}}_{0.67}{\mathrm{Sr}}_{0.33}\mathrm{Mn}{\mathrm{O}}_{3}$ (LSMO)-$\mathrm{Y}{\mathrm{Ba}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7}$ (YBCO)-${\mathrm{La}}_{0.67}{\mathrm{Sr}}_{0.33}\mathrm{Mn}{\mathrm{O}}_{3}$ (LSMO) epitaxial trilayers through resistivity, ac susceptibility, and magnetization measurements. ferromagnetic LSMO layers possessing in-plane suppress the critical...
The intermetallic compound NiBi3 belongs to the interesting class of superconductors that are based on strong ferromagnetic elements. Although has been grown in single-crystal form and also demonstrated at interface Ni Bi layers, uniform thin films have yet appear literature. In this work, we explored codeposition method, wherein high-purity metals evaporated simultaneously controlled rates, study dynamics involved formation films. We used Rutherford backscattering spectrometry (RBS)...
Magnetotransport measurements are performed over a broad range of temperature (T) and magnetic field (H) on highly degenerate n-type Zn(1-x)Co(x)O [Formula: see text] epitaxial films. The cobalt-free samples characterized by metallic resistivity ρ(T) down to 2 K, negative predominantly isotropic magnetoresistance (MR) optical transmission above 85% in the visible electromagnetic spectrum. X-ray diffraction show that while for text], all cobalt atoms occupy tetrahedral sites wurtzite...
Zinc oxide twin nanorods, with two identical crystalline sections connected by an amorphous layer, were reproducibly grown using a simple one-step hydrothermal technique. The thickness of the layer between segments was tunable growth parameters, as confirmed high resolution transmission electron microscopy. photoluminescence spectra these nanorods exhibit strong near band edge emission in UV range, convoluted phonon sidebands. De-convolution analyses showed that interlayers act effective...
We have studied the superconducting proximity effect in a series of e-beam evaporated Bi-Ni-Bi trilayers, where diffusion Bi into Ni spontaneously formed NiBi3 layers at both Ni-Bi interfaces, effectively resulting superconductor-ferromagnet-superconductor (S-F-S) trilayers. The thickness top and bottom was found to be different with slightly transition temperatures. Both resistive temperatures S-F-S trilayers showed 0-π crossover as function ferromagnetic thickness. zero bias conductance...