Microstructure and critical current density in MgB.sub.2./sub. bulk made of 4.5 wt% carbon-coated boron

0477618 - FZÚ 2018 RIV GB eng C - Conference Paper (international conference)
Higuchi, M. - Muralidhar, M. - Jirsa, Miloš - Murakami, M.
Microstructure and critical current density in MgB₂ bulk made of 4.5 wt% carbon-coated boron.
Journal of Physics: Conference Series. Vol. 871. Bristol: IOP Publishing, 2017, s. 1-5, č. článku 012059. ISSN 1742-6588.
[International Symposium on Superconductivity /29./, ISS 2016. Tokyo (JP), 13.12.2016-15.12.2016]
Institutional support: RVO:68378271
Keywords : MgB₂ * bulk superconductors * microstructure * critical currents * carbon coated boron
OECD category: Condensed matter physics (including formerly solid state physics, supercond.)

Superconducting performance and its uniformity was studied in the single-step sintered MgB2 bulk prepared with 4.5 wt% of carbon in the carbon-encapsulated boron. The 20 mm in diameter MgB2 pellet was cut into several pieces from bottom to top and the microstructure, superconducting transition temperature (Tc onset), and critical current density at 20 K were studied. DC magnetization measurements showed a sharp superconducting transition with onset Tc at around 35.5 K in all positions. SEM analysis indicated a dispersion of grains between 200 and 300 nm in size, as the main pinning medium in this MgB2 superconductors. The critical current density at 20 K was quite uniform, around 330 kA/cm2 and 200 kA/cm2 at self-field and 1 T, respectively, for all measured positions. The results indicate that the carbonencapsulated boron is very promising for production of high quality bulk MgB2 material for various industrial applications.
Permanent Link: http://hdl.handle.net/11104/0273914