相关论文: Surface barrier and bulk pinning in MgB$_2$ superc…
Bulk samples of MgB2 have been formed by hot isostatic pressing (HIPping) of commercial powder at 100MPa and 950=B0C. The resulting material is 100% dense with a sharp superconducting transition at 37.5K. Microstructural studies have…
Bulk and surface state contributions to the electrical resistance of single-crystal samples of the topological Kondo insulator compound SmB6 are investigated as a function of crystal thickness and surface charge density, the latter tuned by…
The pinning properties of type-II superconductors can be efficiently controlled by using laterally nanostructured ferromagnet / superconductor bilayers. This will be illustrated by studying the flux pinning in thin superconducting Pb films…
Vortex pinning in a type-II superconducting Pb film covering a Co/Pt multilayer with perpendicular magnetic anisotropy is investigated. Different stable magnetic domain patterns like band and bubble domains can be created in the Co/Pt…
By doping MgB_2 superconductor with SiC nano-particles, we have successfully introduced pinning sites directly into the crystal lattice of MgB_2 grains (intra-grain pinning). It became possible due to the combination of counter-balanced Si…
The boundary-induced scaling of three-dimensional random field Ising magnets is investigated close to the bulk critical point by exact combinatorial optimization methods. We measure several exponents describing surface criticality:…
Nanocrystalline MgB$_2$ produced by mechanical alloying has been shown to exhibit enhanced superconducting properties such as increased pinning and higher critical currents. However, the effects of the synthesis process on the intrinsic…
Superconducting properties of bulk, dense, pure MgB2 and doped (Mg1-xAx)B2 samples with A = Na, Ca, Cu, Ag, Zn and Al were studied for compositional ranges 0 < x < 0.20. The effect on pinning properties and critical current were…
The microstructure of the MgB2 superconductor sintered at high temperature under a high pressure of about 3 GPa was investigated by using a high-resolution transmission electron microscope (HRTEM). The TEM images did not show any pores in…
Polycrystalline MgB2 samples with 10 wt % silicon powder addition were prepared by an in-situ reaction process. Two different Si powders, one with coarse (44 mm) and the other with nano-size (<100 nm) particles were used for making samples.…
In this paper we introduce a novel method for fabricating MgB$_2$/MgO multilayers and demonstrate the potential for using them as a new model for disordered superconductors. In this approach we control the annealing of the MgB$_2$ to yield…
We have fabricated a series of iron-sheathed superconducting wires prepared by the powder-in-tube technique from (MgB_2)_{1-x}:(Mg+2B)_x initial powder mixtures taken with different proportions, so that x varies from 0 to 1. It turned out…
Nearly a decade after the discovery of topological insulators (TIs), the important task of identifying and characterizing their topological surface states through electrical transport experiments remains incomplete. The interpretation of…
We demonstrate direct evidence of possible surface superconductivity on small, well-shaped MgB2 single crystals. Transport measurements in the range H < 1.6 Hc2^c, where Hc2^c is the bulk upper critical field for the c axis, show non-Ohmic…
Heterogeneous sonochemical method was applied for synthesis of novel superconducting nanocomposites consisting of magnetic (and/or nonmagnetic) nanoparticles embedded into the bulk of ceramic superconductors. In addition to in-situ…
The present article reports a method for the average grain size evaluation of superconducting nano-particles through their magnetic properties. The use of SQUID magnetometry to determine the average MgB2 particle size was investigated and…
We report the observation of electric-field-induced superconductivity on the surface of bulk polycrystalline MoS2 using electric double-layer doping. A gate voltage applied in an ionic liquid environment systematically increased carrier…
Powdered and sintered MgB2 samples have been characterized through magnetic measurements performed from T = 5 K up to few degrees above the transition temperature of about 39 K. We found that the sintered samples behave as well-connected…
We discuss the temperature, frequency, and power-dependent surface resistance of the boride superconductor MgB2 in relation to possible applications for passive microwave devices. The data available in the literature are compared with…
The electrochemical gating technique is a powerful tool to tune the \textit{surface} electronic conduction properties of various materials by means of pure charge doping, but its efficiency is thought to be hampered in materials with a good…