Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

TT: Fachverband Tiefe Temperaturen

TT 30: Superconductivity - Poster Session

TT 30.4: Poster

Montag, 31. März 2014, 15:00–19:00, P2

High trapped fields in MgB₂ bulk samples — •Wolfgang Häßler¹, Günter Fuchs¹, Konstantin Nenkov¹, Juliane Scheiter¹, Axel Handstein¹, Bernhard Holzapfel^1,2, and Ludwig Schultz¹ — ¹Leibniz Institut für Festkörper- und Werkstoffforschung (IFW) Dresden, P.O. Box 270116, 01171 Dresden — ²Karlsruhe Institute of Technology (KIT), Institute for Technical Physics, P.O. Box 3640, 76021 Karlsruhe

MgB₂ is a promising superconductor for bulk trapped field magnets operating between 15 and 20 K. The absence of weak-link behavior in MgB₂ offers the advantage of a simple and cost-effective technique for fabrication of large bulks with high trapped fields. Bulk superconducting MgB₂ samples, 20 mm in diameter, were prepared by hot-pressing of high energy milled Mg and B powders using nanosized boron powders. High maximum trapped fields of 5.4 T were obtained at 12 K by Hall probe measurements at the centre of the bulk surface in one of the trapped field magnets (height 8 mm). For short MgB₂ samples (height 1.6 mm), trapped fields up to 3.2 T were achieved at 15 K. These high trapped fields are related to extremely high critical current densities up to 10⁶A/cm² at 15 K indicating strong pinning due to nano-crystalline MgB₂ grains. The measured trapped field of 5.4 T at 12 K is the highest reported so far. By increasing height and/or diameter of these bulk MgB₂ samples, even higher trapped fields are expected which demonstrates the large potential of MgB₂ trapped field magnets in the field of engineering applications at temperatures between 15 and 20 K