Berlin 2015 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 17: Superconductivity: Properties and Electronic Structure
TT 17.11: Vortrag
Montag, 16. März 2015, 17:45–18:00, H 2053
Microstructural characterization of Bulk MgB2 — •Alex Wiederhold1, Michael Koblischka1, Kazuo Inoue2, Miryala Muralidhar2, Masato Murakami2, Kévin Berger3, Bruno Douine3, Thomas Hauet4, Jacques Noudem5, and Uwe Hartmann1 — 1Institute of Experimental Physics, Saarland University, P. O. Box 151150, D-66123 Saarbrücken, Germany — 2Department of Material Science and Engeneering, Shibaura Institute of Technology, 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548, Japan — 3GREEN, Université de Lorraine, Vandœuvre-les-Nancy, France — 4Institute Jean Lamour, Université de Lorraine, Vandœuvre-les-Nancy, France — 5CRISMAT-CNRS, Cherbourg, France
A series of disk-shaped bulk MgB2 superconductors (sample diameter up to 4 cm) was prepared in order to improve the performance for superconducting super-magnets. Several samples were fabricated using a solid state reaction in pure Ar atmosphere from 750 to 950 ∘C to obtain the highest critical current density (jc) as well as large trapped field values. Magnetization and transport measurements revealed that at the low reaction temperatures flux pinning at grain boundaries is dominant, which is decreasing on increasing temperature. At the highest reaction temperature, jc was found to increase again indicating a change of the pinning mechanism [1]. In order to clarify this behavior the samples were characterized in detail by means of transmission electron microscopy (TEM) and transmission electron backscatter diffraction (t-EBSD).
[1] M.R.Koblischka et al., IEEE Trans. Magn. (in press).