"

Cookies ussage consent

Our site saves small pieces of text information (cookies) on your device in order to deliver better content and for statistical purposes. You can disable the usage of cookies by changing the settings of your browser. By browsing our site without changing the browser settings you grant us permission to store that information on your device.

I agree, do not show this message again.

Qualitative comparative analysis of MgB2 powder-in-tube wires: superconductivity and X-ray cone-bean microtomography

P. BADICA1,* , I. TISEANU2, G. ALDICA1, T. CRACIUNESCU2, V. SANDU1, G. JAKOB3, M. RINDFLEISCH4

Affiliation

  1. National Institute for Materials Physics, 077125 Bucharest, Romania
  2. National Institute for Lasers, Plasma and Radiation Physics, Bucharest, 077125 Romania
  3. Mainz University, Institute of Physics, 55128 Mainz, Germany
  4. Hyper Tech Research Inc, Columbus, OH 43228, USA

Abstract

Commercial wires of MgB2 with different architectures and two different heat treatments were characterized with respect to their superconducting properties (Tc, Jc, Hirr, pinning force, macro flux jumps behaviour) through magnetic measurements and were visualized by 3D x-ray micro-tomography (XRT). For a particular architecture, heat treatment conditions of 625 C/3 hrs or 700 C/30 min produced relatively small differences, whereas the architecture of the wires showed a strong influence on superconducting characteristics. XRT checks the integrity of the wires easily detecting in a non-invasive way 3D macro defects and shows their hidden extended shape. XRT also allows a comparative geometry analysis between similar elements (e.g. filaments or filaments-matrix interfaces) from a particular wire or from wires with different architectures. Namely, XRT shows that the geometrical perfection (defined as the degree of departure of the geometry from the designed one) of the inner MgB2 filaments from the wires with 18 elements was lower than for the outermost ones from the same wires and was also lower than for the filaments from the wires with 7 elements. It is proposed that these results of geometrical perfection correlate with better overall superconducting quality of the wires with 7 filaments (except for the stronger presence of macro flux jumps in the wires with 7 filaments)..

Keywords

MgB2, wires, Critical current density, Microtomography, Pinning force.

Submitted at: Feb. 20, 2015
Accepted at: Oct. 28, 2015

Citation

P. BADICA, I. TISEANU, G. ALDICA, T. CRACIUNESCU, V. SANDU, G. JAKOB, M. RINDFLEISCH, Qualitative comparative analysis of MgB2 powder-in-tube wires: superconductivity and X-ray cone-bean microtomography, Journal of Optoelectronics and Advanced Materials Vol. 17, Iss. 11-12, pp. 1636-1649 (2015)