A5049326270- Shape Memory Alloy Transformations
- Magnetic and transport properties of perovskites and related materials
- Electron and X-Ray Spectroscopy Techniques
- Quasicrystal Structures and Properties
- Surface and Thin Film Phenomena
- X-ray Diffraction in Crystallography
- Advanced Chemical Physics Studies
- Heusler alloys: electronic and magnetic properties
- Electronic and Structural Properties of Oxides
- Semiconductor materials and devices
- ZnO doping and properties
- Crystallization and Solubility Studies
- Rare-earth and actinide compounds
- Metal and Thin Film Mechanics
- Copper-based nanomaterials and applications
- Magnetic Properties and Applications
- Advanced Condensed Matter Physics
- Ga2O3 and related materials
- Ion-surface interactions and analysis
- Graphene research and applications
- X-ray Spectroscopy and Fluorescence Analysis
- Transition Metal Oxide Nanomaterials
- nanoparticles nucleation surface interactions
- Nanocluster Synthesis and Applications
- Magnetic Properties of Alloys
R. G. Kar Medical College and Hospital
2024
Medical College and Hospital, Kolkata
2024
Indian Institute of Technology Kanpur
2024
UGC DAE Consortium for Scientific Research
2013-2024
Homi Bhabha National Institute
2023
Amity University
2023
Sardar Patel University
2023
Devi Ahilya Vishwavidyalaya
2020
Indira Gandhi Centre for Atomic Research
2020
Inter-University Accelerator Centre
2020
The electronic structures of a wide range early transition-metal (TM) compounds, including Ti and V oxides with metal valences ranging from 2+ to 5+ formal d-electron numbers 0 2, have been investigated by configuration-interaction cluster model analysis the core-level 2p x-ray photoemission spectra (XPS). Inelastic energy-loss backgrounds calculated experimentally measured electron-energy-loss (EELS) were subtracted XPS remove extrinsic loss features. Parameter values deduced for...
It is shown that the local spin-density approximation describes well electronic structures of perovskite $\mathrm{La}M{\mathrm{O}}_{3}$ ( $M\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}$ Mn, Fe, Co, Ni) for ground-state and single-electron excited-state properties. Inclusion details crystal distorted from cubic structure crucial to reproduce different magnetic insulating states. Calculated x-ray photoemission spectra are in very good agreement with experimental ones, its angular...
5% negative magnetoresistance (MR) at room temperature has been observed in bulk Ni_{2+x}Mn_{1-x}Ga. This indicates the possibility of using Ni_{2+x}Mn_{1-x}Ga as magnetic sensors. We have measured MR ferromagnetic state for different compositions (x=0-0.2) austenitic, pre-martensitic and martensitic phases. is found to increase with x. While x=0 varies almost linearly austenitic phases, phase it shows a cusp-like shape. explained by changes twin domain structures phase. In phase, which does...
We predict the existence of a new ferromagnetic shape memory alloy Ga_2MnNi using density functional theory. The martensitic start temperature (T_M) is found to be approximately proportional stabilization energy phase (deltaE_tot) for different alloys. Experimental studies performed verify theoretical results show that at room and T_M T_C are 780K 330K, respectively. Both from theory experiment, transition volume conserving indicative behavior.
The phase diagrams of magnetic shape-memory Heusler alloys, in particular, ternary Ni-Mn-Z and quarternary (Pt, Ni)-Mn-Z alloys with Z = Ga, Sn, have been addressed by density functional theory Monte Carlo simulations. Finite temperature free energy calculations show that the phonon contribution stabilizes high-temperature austenite structure while at low temperatures magnetism band Jahn-Teller effect favor modulated monoclinic 14M or nonmodulated tetragonal structure. substitution Ni Pt...
Spin valves have revolutionized the field of magnetic recording and memory devices. are generally realized in thin film heterostructures, where two ferromagnetic (FM) layers separated by a nonmagnetic conducting layer. Here, we demonstrate spin-valve-like magnetoresistance at room temperature bulk ferrimagnetic material that exhibits shape effect. The origin this unexpected behavior Mn(2)NiGa has been investigated neutron diffraction, magnetization, ab initio theoretical calculations....
In recent times, the environmental and pure water crisis requires many types of scientific evaluation to handle issues caused by different pharmaceutical drugs. The current work involves synthesis ternary hybrid nanomaterials based on Ti3C2MXene–BiFeO3 (BFO)–ZnO their applications as photocatalysts for disintegration antacids. introduction two-dimensional (2D) MXene layer in BFO–ZnO heterostructures not only creates additional reaction hotspots but also enhances charge-transport properties...
The equilibrium structure and electronic properties of a ferromagnetic shape memory alloy ${\mathrm{Ni}}_{2}\mathrm{Mn}\mathrm{Ga}$ have been studied for both the martensitic austenitic phases by full potential linearized augmented plane wave method. We report stable phase at $c∕a=0.97$ lattice constants are in good agreement with experimentally reported values. Ni $3d$ ${e}_{g}$ related minority-spin peak density states (DOS) near Fermi level $({E}_{F})$ splits into $3{d}_{{z}^{2}}$...
Electronic structures of metallic ${\mathrm{LaNiO}}_{3}$ and insulating ${\mathrm{NdNiO}}_{3}$ are investigated using electron spectroscopies as well band-structure model-Hamiltonian calculations. It is shown that there an increase in the transfer integral, ${\mathit{t}}_{\mathit{p}\mathit{d}}$ compared to though ${\mathit{U}}_{\mathit{d}\mathit{d}}$ \ensuremath{\Delta} very similar. A phase diagram obtained with a multiband Hubbard model explains metal-insulator transition anomalous...
The effect of acid/base functional‐groups associated with platinized‐carbon electrodes on their catalytic activity toward electro‐oxidation methanol in sulfuric acid electrolyte at 60°C is studied. Platinized‐carbon small amounts functional groups exhibit higher compared to those large concentrations acidic/basic surface functionalities. overpotential for oxidation minimum platinized carbons pHzpc values between 6 and 7. An x‐ray photoelectron spectroscopic study various suggests that the...
The crystal structure of ${\mathrm{Ni}}_{2+x}{\mathrm{Mn}}_{1\ensuremath{-}x}\mathrm{Ga}$ has been studied as a function composition $(x)$ by powder x-ray diffraction. For ${\mathrm{Ni}}_{2.24}{\mathrm{Mn}}_{0.75}\mathrm{Ga}$, where one-fourth the Mn atoms are replaced Ni, experimentally determined lattice constants in good agreement with theoretical equilibrium calculated minimization total energy using full potential linearized augmented plane-wave method....
The electronic structure of Mn2NiGa has been studied using density functional theory and photoemission spectroscopy. lower-temperature tetragonal martensitic phase with c/a= 1.25 is more stable compared to the higher-temperature austenitic phase. ferrimagnetic in both phases. calculated valence band spectrum, optimized lattice constants magnetic moments are good agreement experiment. majority-spin Fermi surface (FS) expands phase, while minority-spin FS shrinks. nesting indicates occurrence...
We have investigated the magnetic and magnetocaloric properties of HoMnO3 single crystal. displays a series complicated phase transitions due to long range ordering Mn3+ Ho3+ moments. Field variation in magnetization generates metamagnetic transition produces an entropy change 13.1 J/kg K at 7 T vicinity antiferromagnetic temperature Ho3+. The values adiabatic (∼6.5 K) relative cooling power (∼320 J/kg) for field are also appreciable consider as refrigerant low temperature.
Recently, Liu et al. [Phys. Rev. B 74, 054435 (2006)] published the electronic structure of ${\text{Mn}}_{2}\text{NiGa}$ by using ab initio spin-polarized density functional theory. In martensitic phase, they report a large decrease in Mn and Ni local magnetic moments to almost zero increase states at Fermi level. By total energy minimization, considering various possible starting moment configurations, we show that above mentioned results do not correspond minimum solution. Our are...
Magnetism in Ni-Mn-Z (Z = Ga,In,Sn,Sb) Heusler alloys has so far been predominantly attributed to Rudermann-Kittel-Kasuya-Yoshida type interactions between Mn atoms. We investigate magnetic one such alloy, Ni$_{2}$Mn$_{1.4}$In$_{0.6}$ and attempt explain the origin of antiferromagnetic (AFM) that coexist with ferromagnetic ones. Through combination x-ray absorption spectroscopy circular dichroism (XMCD), we find Ni plays an important role along overall magnetism. A significant hybridization...
We present results of a temperature-dependent high-resolution synchrotron x-ray powder diffraction study sequence phase transitions in $\mathrm{N}{\mathrm{i}}_{2}\mathrm{MnGa}$. Our show that the incommensurate martensite from premartensite and not austenite assumed adaptive model. The transforms to through first order transition with coexistence two phases broad temperature interval $(\ensuremath{\sim}40\phantom{\rule{0.16em}{0ex}}\mathrm{K})$, discontinuous change unit cell volume as also...
The electrical device characteristics of Ni/β-Ga2O3 vertical Schottky barrier diodes (SBDs) were measured in situ during the irradiation 120 MeV Ag7+ swift heavy ions (SHIs). These devices exhibit SHI irradiation-induced degradation with ion fluence ranges 1 × 1010 to 1012 ions/cm2. height is found decrease from 1.11 0.93 eV, and ideality factor increases 1.16 2.06. changes indicate irradiation. A significant four orders increase observed leakage current density 4.04 10−8 1.98 10−4 A/cm2 at...
LaTe3 is a non-centrosymmetric material with time reversal symmetry, where the charge density wave hosted by Te bilayers. Here, we show that hosts Kramers nodal line-a twofold degenerate line connecting reversal-invariant momenta. We use angle-resolved photoemission spectroscopy, functional theory an experimentally reported modulated structure, effective band structures calculated unfolding, and symmetry arguments to reveal line. Furthermore, calculations confirm imposes gapless crossings...
Results of temperature-dependent magnetic susceptibility and powder x-ray diffraction (XRD) measurements on ${\mathrm{Ni}}_{2}{\mathrm{Mn}}_{1.05}{\mathrm{Ga}}_{0.95}$ ${\mathrm{Ni}}_{2.13}{\mathrm{Mn}}_{0.87}\mathrm{Ga}$ shape memory alloys are compared. The transformation behavior these two is found to be entirely different. Detailed LeBail Rietveld analyses XRD data alloy show that the martensite phase belongs Pnnm space group with $7M$ modulation. limits supercooled austenite superheated...