Microstructure and magnetic properties of bulk MgB2 samples

Alex Wiederhold (1) , Michael Rudolf Koblischka (1) , Kazuo Inoue (2) , Muralidhar Miryala (2) , Masato Murakami (2) , Kévin Berger (3) , Bruno Douine (3) , Thomas Hauet (4) , Jacques Noudem (5, 6) , Uwe Hartmann (1)

1 Saarland University [Saarbrücken]
2 Shibaura Institute of Technology
3 GREEN - Groupe de Recherche en Electrotechnique et Electronique de Nancy
4 IJL - Institut Jean Lamour
5 CRISMAT - Laboratoire de cristallographie et sciences des matériaux
6 LUSAC - Laboratoire Universitaire des Sciences Appliquées de Cherbourg

Disk-shaped, bulk MgB2 superconductors (sample diameter up to 4 cm) were prepared in order to improve their performance for use as superconducting super-magnets. Several samples were fabricated using two different processes, one set using a solid state reaction in pure Ar atmosphere at temperatures ranging from 750 to 950 oC, and another type prepared via high-pressure sintering. On both types of samples, 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. 50, 9000504 (2014).

Domaines: Electromagnétisme; Supraconductivité [cond-mat.supr-con]; Energie électrique; Science des matériaux [cond-mat.mtrl-sci]

Alex Wiederhold, Michael Rudolf Koblischka, Kazuo Inoue, Muralidhar Miryala, Masato Murakami, et al.. Microstructure and magnetic properties of bulk MgB2 samples. EUCAS 2015 - 12th European Conference on Applied Superconductivity, Sep 2015, Lyon, France. p. 112, id. 1A-M-P-05.07. ⟨hal-01196641⟩