Related papers: Properties of MgB2 bulk
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…
According to the crystal structure of MgB$_{2}$ and band structure calculations quasi-two-dimensional (2D) boron planes are responsible for the superconductivity. We report on critical fields and resistance measurements of 30 nm thick…
We report a significant enhancement of the upper critical field $H_{c2}$ of different $MgB_2$ samples alloyed with nonmagnetic impurities. By studying films and bulk polycrystals with different resistivities $\rho$, we show a clear trend of…
The superconducting properties of copper-sheathed MgB2 wires fabricated by conventional powder-in-tube techniques and the in-situ reaction procedure are analysed. The influence of the processing conditions and initial (1+x)Mg + 2B (x = 0,…
Superconducting $MgB_2$ wires in Cu, GlidCop or Monel sheath with Nb or Fe barrier are prepared. Wires vary by sheath material, number of superconducting cores and their chemical composition. Wires are HIP-ed (Hot Isostatic Pressing) at…
We report the growth and properties of epitaxial MgB2 thin films on (0001) Al2O3 substrates. The MgB2 thin films were prepared by depositing boron films via RF magnetron sputtering, followed by a post-deposition anneal at 850C in magnesium…
We have developed disk-shaped MgB2 bulk superconducting magnets (20, 30 mm in diameter, 10 mm in thickness) using the in-situ process from Mg and B powders and evaluated the temperature dependence of trapped magnetic field. A pair of two…
Oxygen was systematically incorporated in MBE grown MgB2 films using in-situ post-growth anneals in an oxygen environment. Connectivity analysis in combination with measurements of the critical temperature and resistivity indicate that…
We report on the synthesis and on basic superconducting properties of a completely new Mo_2Re_3B ternary boride. The crystal structure of the Mo_2Re_3B compound is characterised by Pmmm space group and the cell parameters: a=11.626 A,…
Superconducting bulk properties of ternary Nb2 BN are confirmed and are described by means of magnetization, electronic transport and specific-heat measurements. BCS conventional super- conductivity is found with Tc = 4.4 K. Critical fields…
We report on study of the electronic anisotropy of the newly discovered MgB2 superconductor using the in-plane resistivity measurements in magnetic field applied perpendicular and parallel to Mg and B planes of MgB2 single crystals. The…
In this paper we report a new sol-gel method for the fabrication of MgB2 films. Polycrystalline MgB2 films were prepared by spin-coating a precursor solution of Mg(BH_4)_2 diethyl ether on (001)Al2O3 substrates followed with annealing in Mg…
The size effect of the raw B powder on the MgB2 phase formation has been studied by the technique of in-situ high temperature resistivity (HT-rT) measurement. The onset temperature, Tonset, and the completion temperature, TPF, of the phase…
We report measurements on MgB2 up to ~40GPa. Increasing pressure yields a monotonous decrease of the lattice parameters and of the c/a ratio, but no structural transition down to parameters smaller than those of AlB2. The transition…
The complex conductivity of a MgB2 film has been investigated in the frequency range 4 cm^{-1}< nu < 30 cm^{-1} and for temperatures 2.7 K < T <300 K. The overall temperature dependence of both components of the complex conductivity is…
The critical current density of four MgB2 samples was measured inductively and for one of them also by transport. Pure phased and dense bulk samples yield a critical current density which in value, as well as in its magnetic field and…
Case studies of $1T$-TiSe$_2$ and YBa$_2$Cu$_3$O$_{7-\delta}$ have demonstrated that x-ray diffraction (XRD) studies can be used to trace even subtle structural phase transitions which are inherently connected with the onset of…
Doping effect of diamond nanoparticles on the superconducting properties of MgB2 bulk material has been studied. It is found that the superconducting transition temperature Tc of MgB2 is suppressed by the diamond-doping, however, the…
Superconductors with persistent zero-resistance currents serve as permanent magnets for high-field applications requiring a strong and stable magnetic field, such as magnetic resonance imaging (MRI). The recent global helium shortage has…
We report the study of the polycrystalline MgB2 phase formation during the fabrication processes. Three major phases are identified in different sintering temperature ranges according to the corresponding superconducting properties and the…