A5012961514- Physics of Superconductivity and Magnetism
- Iron-based superconductors research
- Superconductivity in MgB2 and Alloys
- Rare-earth and actinide compounds
- Magnetic and transport properties of perovskites and related materials
- Advanced Sensor and Energy Harvesting Materials
- Conducting polymers and applications
- Supercapacitor Materials and Fabrication
- Advanced Condensed Matter Physics
- Advancements in Battery Materials
- Hydrogen Storage and Materials
- Magnetic properties of thin films
- Magnetic Properties of Alloys
- Inorganic Fluorides and Related Compounds
- Intellectual Capital and Performance Analysis
- Quantum and electron transport phenomena
- Corporate Taxation and Avoidance
- Transition Metal Oxide Nanomaterials
- Thermal Expansion and Ionic Conductivity
- Boron and Carbon Nanomaterials Research
- Advanced Chemical Physics Studies
- Graphene research and applications
- Electronic and Structural Properties of Oxides
- High-pressure geophysics and materials
- Metamaterials and Metasurfaces Applications
Ferdowsi University of Mashhad
2015-2024
Renewable Energies Agency
2021
ARC Centre of Excellence for Electromaterials Science
2010-2018
University of Wollongong
2008-2018
Sabzevar University of Medical Sciences
2004-2012
Hakim Sabzevari University
2012
Kista Photonics Research Center
2002-2004
KTH Royal Institute of Technology
2000-2003
We report that the $(\text{Ba},\text{K}){\text{Fe}}_{2}{\text{As}}_{2}$ crystal with ${T}_{c}=32\text{ }\text{K}$ shows a pinning potential, ${U}_{0}$, as high ${10}^{4}\text{ }\text{K}$, ${U}_{0}$ showing very little field dependence. The single crystals become isotropic at low temperatures and magnetic fields, resulting in rigid vortex lattice, even fields close to ${\text{H}}_{c2}$. vortices observed two-dimensional (2D) distinguish this compound from 2D high-${T}_{c}$ cuprate...
An efficient procedure for the fabrication of highly conductive carbon nanotube/graphene hybrid yarns has been developed. To start, arrays vertically aligned multi‐walled nanotubes (MWNT) are converted into indefinitely long MWNT sheets by drawing. Graphene flakes then deposited onto electrospinning to form a composite structure that is transformed yarn filaments twisting. The process scalable on an industrial scale. Prepared materials characterized electron microscopy, electrical,...
Hybrid polypyrrole (PPy)-multi walled carbon nanotube (MWNT) yarns were obtained by chemical and electrochemical polymerization of pyrrole on the surface within porous interior twisted MWNT yarns. The material was characterized scanning electron microscopy, electrochemical, mechanical electrical measurements. It found that hybrid PPy-MWNT possessed significantly higher strength (over 740 MPa) Young's modulus 54 GPa) than pristine yarn. also exhibited substantially conductivity 235 S cm(-1))...
The vortex liquid-to-glass transition has been studied in Ba0.72K0.28Fe2As2 (BaK-122), Ba(Fe0.91Co0.09)2As2(BaCo-122), and Ba(Fe0.95Ni0.05)2As2(BaNi-122) single crystal with superconducting temperature, Tc = 31.7, 17.3, 18 K, respectively, by magnetoresistance measurements. For temperatures below Tc, the resistivity curves were measured magnetic fields within range of 0 ≤ B 13 T, pinning potential was scaled according to a modified model for liquid resistivity. Good scaling ρ(B, T) effective...
Abstract Pressure is well known to significantly raise the superconducting transition temperature, T c , in both iron pnictides and cuprate based superconductors. Little work has been done, however, on how pressure can affect flux pinning critical current density Fe-based Here, we propose use hydrostatic enhance polycrystalline pnictide bulks. We have chosen Sr 4 V 2 O 6 Fe As samples as a case study. demonstrate that up 1.2 GPa not only increase from 15 K (underdoped) 22 K, but also...
Flux-pinning mechanism of ${\text{MgB}}_{2}$ doped with $10\text{ }\text{wt}\text{ }%$ silicone-oil sintered at low and high temperatures has been investigated by magnetic measurements. The field dependence the critical current density, ${j}_{c}(B)$, was analyzed within collective pinning model. A crossover field, ${B}_{\text{sb}}$, from single vortex to small bundle-pinning regime observed. For both types samples, temperature ${B}_{\text{sb}}(T)$ is in good agreement $\ensuremath{\delta}l$...
In this work, we present the following important results: 1) We introduce a new Si source, liquid SiCl4, which is free of C, to significantly enhance irreversibility field (Hirr), upper critical (Hc2), and current density (Jc), with little reduction in temperature (Tc). 2) Although can not incorporate into crystal lattice, found a-axis lattice parameter, same extent as for carbon doping. 3) The SiCl4 treated MgB2 shows much higher Jc superior dependence above 20 K than undoepd doped various...
The mechanical and the electrical properties of polypyrrole (PPy) fibers electrochemically deposited PPy films were studied. It was found that showed a significantly higher strength than due to better orientation molecular structure. prepared had conductivity at high temperature. At low temperature, conductivity. results analyzed in frame three-dimensional variable range hopping model. room temperature average distance for about 4 Å while it increases 5.7 Å. This corresponds 1 2 monomer...
Tremendous efforts towards improvement in the critical current density (Jc) of iron based superconductors (FeSCs), especially at relatively low temperatures and magnetic fields, have been made so far through different methods, resulting real progress. Jc high fields still needs to be further improved, however, order meet requirements practical applications. Here, we demonstrate a simple approach achieve this. Hydrostatic pressure can significantly enhance NaFe0.97Co0.03As single crystals by...
The flux pinning mechanisms of nano-Si-doped MgB2 are reported in this work. field dependence the critical current density, Jc(B), was analyzed within collective model. We found that for both δl pinning, i.e., associated with charge-carrier mean free path fluctuations, and δTc which is spatial fluctuations transition temperature, coexist samples, while Hc2 increases greatly increasing nano-Si doping level. However, their contributions strongly temperature dependent. dominant at low...
In this work, ternary nanocomposites of iron (II and III) oxides/reduced graphene oxide/polypyrrole (iron oxide/rGO/PPy) have been prepared as the electrode materials supercapacitor. These were via a facile two-step process including, synthesis oxides/rGO binary nanohybrids by one-pot chemical-microwave method in situ oxidative polymerization. The morphological structural characterizations these demonstrated decoration oxides on GO sheets proper formation oxide/rGO/PPy nanocomposites....
The vortex pinning mechanisms of Ba0.72K0.28Fe2As2 single crystal have been studied systematically as a function temperature and magnetic field. dependence the critical current density, Jc(T), was analysed within collective model at different fields. It found that both δl mechanism, i.e., associated with charge-carrier mean free path fluctuation, δTc which is spatial fluctuations transition temperature, coexist in fields smaller than 4 T. Their contributions are strongly field dependent. At...
We report the effects of C4+-irradiation on superconducting properties BaFe1.9Ni0.1As2 single crystal. The crystal before and after was characterized by magnetic, magneto-transport magneto-optical techniques over a wide range magnetic fields (0–13 T) temperatures (2–200 K). demonstrate that significantly enhances in-field critical current density (by factor up to 1.5 at 5 K) induces enhanced flux jumping 2 K, with only small degradation 0.5 temperature, Tc. vortex phase diagram describing...
The impact of hydrostatic pressure up to 1.2 GPa on the critical current density (J c ) and nature pinning mechanism in MgB 2 have been investigated within framework collective theory.We found that can induce a transition from regime where is controlled by spatial variation temperature (δT mean free path (δℓ).Furthermore, T low field J are slightly reduced, although drops more quickly at high fields than ambient pressure.We raises anisotropy reduces coherence length, resulting weak...
Underdoped BaFe1.9Co0.1As2 single crystal was studied by angular dependence of magneto-transport at fields up to 13 T over a wide range temperature. Our results show that pinning potential, Uo, decreases slightly for θ ≤ 45° and remains constant ≥ 45°, while the upper critical field, Hc2, irreversibility Hirr, increase with θ. According anisotropic Ginzburg-Landau theory, anisotropy determined scaling resistivity under different magnetic below superconducting temperature, Tc. Anisotropy, Γ,...