Berlin 2015 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 17: Superconductivity: Properties and Electronic Structure

TT 17.12: Vortrag

Montag, 16. März 2015, 18:00–18:15, H 2053

Magnetic characterization of Ag-addet Bulk MgB₂ — •Alex Wiederhold¹, Michael Koblischka¹, Kazuo Inoue², Miryala Muralidhar², Masato Murakami², Thomas Hauet³, 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 — ³Institute Jean Lamour, Université de Lorraine, Vandœuvre-les-Nancy, France

n earlier studies, it was found that bulk sintered MgB₂ samples contained numerous voids which hinder the current flow. Therefore, a series of bulk MgB₂ superconductors with Ag contents of 0-10 wt% was prepared in order to improve the critical current densities and the mechanical performance. Several samples were fabricated using a solid state reaction in pure Ar atmosphere at the optimal reaction temperature of 775 ^∘C. Thorough microstructural observations obtained from scanning electron microscopy (SEM) and atomic force microscopy (AFM) indicate that metallic Ag particles are embedded in the void regions.Furthermore, nanometer-sized AgMg₃ particles are also present within the MgB₂ matrix, leading to improved flux pinning. Small samples cut from the bulks were characterized by transport measurements (R(T,B) and I/V characteristics) in magnetic fields up to 8 T and by magnetization loops measured using a SQUID magnetometer.