Related papers: Defect structures in MgB2 wires introduced by hot …
Superconducting Ag or Cu sheathed MgB2 wires have been fabricated by conventional powder-in-tube techniques. The in-situ reaction of Mg and B powders with atomic proportions of 1:2 and 1.33:2 inside Ag or Cu tubes at low temperatures have…
For technical application in windings of coils, transformers or motors, a reinforcement of MgB2 wires and tapes is necessary to withstand applied stresses and strains and to avoid cracks in the filaments. Therefore, the response of the…
We present electrical transport, magnetization, and specific heat measurements on bulk MgB2 samples (T_{c} = 38.5 K) synthesized under 200 MPa pressure using a process based on hot isostatic pressing with cooling under pressure. The samples…
We report the successful imaging of flux vortices in single crystal MgB2 using transmission electron microscopy. The specimen was thinned to electron transparency (350 nm thickness) by focussed ion beam milling. An artefact of the thinning…
Here we report a systematic study of superconductive properties of mono-filamentary MgB2-based wires, manufactured with different filling technique. A detailed comparison of the influence of filling technique and final heat treatment on…
The Powder-In-Tube process has been employed to fabricate tape-like conductors with a strong metallic sheath and based on the newly discovered MgB2 superconducting phase. Long superconducting tapes have been prepared by packing reacted MgB2…
The normal state and superconducting properties of MgB2 and Mg1-xAlxB2 are discussed based on structural, transport, and high pressure experiments. The positive Seebeck coefficient and its linear temperature dependence for Tc<T<160 K…
We prepared and characterized monofilamentary MgB2 wires with a mechanically reinforced composite sheath of Ta(Nb)/Cu/steel, which leads to dense filaments and correspondingly high transport currents up to Jc = 10^5 A/cm^2 at 4.2 K, self…
We have successfully prepared the MgB2 superconducting bulk and powdered materials by the method of combustion synthesis. The starting materials used in this study were powders of Mg and B. X-ray powder diffraction pattern was well assigned…
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…
The review considers bulk MgB2-based materials in terms of their structure, superconducting and mechanical properties. Superconducting transition temperatures of 34.5-39.4 K, critical current densities of 1.8-1.0 x E6 A/sq.cm in self field…
The superconductivities of samples prepared by several procedures were found to degrade under ambient environment. The degradation mechanism was studied by measuring the change of surface chemical composition of dense MgB2 pellets (prepared…
A model for highly non-linear transport in heterogeneous media consisting of anisotropic particles with a preferred orientation is proposed and applied to the current transport in weakly textured magnesium diboride, MgB2. It essentially…
We synthesized hexagonal-disc-shaped MgB2 single crystals under high-pressure conditions and analyzed the microstructure and pinning properties. The lattice constants and the Laue pattern of the crystals from X-ray micro-diffraction showed…
Monofilamentary MgB2-wires with a 2- or 3-component sheath containing mechanical reinforcing stainless steel (SS) were prepared and characterized. In direct contact to the superconductor Nb, Ta or Fe was used. For a selection of samples…
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…
The influence of anisotropy on the transport current in MgB$_2$ polycrystalline bulk samples and wires is discussed. A model for the critical current density is proposed, which is based on anisotropic London theory, grain boundary pinning…
The high transition temperature and low surface resistance of MgB2 attracts interest in its potential application in superconducting radio frequency accelerating cavities. However, compared to traditional Nb cavities, the viability of MgB2…
Monofilamentary MgB2-wires with a mechanical tough Nb/Cu/steel or Fe/steel sheath were prepared and characterized. The steel content was varied to investigate the reinforcement effect and the consequences for the superconducting properties…
Magneto-optical imaging reveals that in superconducting films of MgB2 a transport current creates avalanche-like flux dynamics where highly branching dendritic penetration patterns are formed. The instability is triggered when the current…