arXiv subjects

A. Presz

Publications and source records attributed to A. Presz.

3 recordsLinked to original sources

arXiv2014

The high gas pressure HIP influence on structure and transport properties of $MgB_2$ superconductors of single and multicore composition

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 various temperatures ($600-800^oC$) and pressure (up to 1.4 GPa). SEM pictures of cross sections are investigated in order to investigate barrier reactivity and cracking, superconducting material density and grain sizes. Transport measurements are made in magnetic field up to 14 T leading to calculations of critical current density $j_c$ and global pinning force $F_p$. Improvement of transport properties due to higher density of superconducting material is shown.

cond-mat.supr-con↗

arXiv2011

Synthesis, Crystal Growth and Epitaxial Layer Deposition of FeSe0.88 Superconductor and Other Poison Materials by Use of High Gas Pressure Trap System

The FeSe samples in the form of polycrystals, single crystals and thin films have been prepared and characterized. The synthesized material has been hot isostatically pressed under pressure of 0.45 GPa of 5N purity argon with the use of the high gas pressure trap system (HGPTS). Thin films have been fabricated by the mixed procedures with the use of DC sputtering from various types of targets and processed employing the HGPTS. The used HGPTS assures a full separation of the active volume for synthesis or crystal growth of material and the inert gas medium. The obtained FeSe0.88 samples have Tc between 8 and 12 K. The samples have been characterized by SEM, EDX, XRD, magnetic susceptibility and resistivity measurements.

cond-mat.supr-con↗

arXiv2007

GaAs:Mn nanowires grown by molecular beam epitaxy of (Ga,Mn)As at MnAs segregation conditions

GaAs:Mn nanowires were obtained on GaAs(001) and GaAs(111)B substrates by molecular beam epitaxial growth of (Ga,Mn)As at conditions leading to MnAs phase separation. Their density is proportional to the density of catalyzing MnAs nanoislands, which can be controlled by the Mn flux and/or the substrate temperature. Being rooted in the ferromagnetic semiconductor (Ga,Mn)As, the nanowires combine one-dimensional properties with the magnetic properties of (Ga,Mn)As and provide natural, self assembled structures for nanospintronics.

cond-mat.mtrl-sci↗