[Zurück]

P. Kovàc, K. Hense, T. Melisek, I. Husek, H. Kirchmayr:
"I_c anisotropy and I_c hysteresis in MgB₂/Fe/Cu tape";
Superconductor Science and Technology, 15 (2002), S. 1037 - 1039.

Ic anisotropy and Ic hysteresis in MgB2/Fe/Cu tape
P Kovác1, K Hense2, T Meli?ek1, I Hu?ek1 and H Kirchmayr2
1 Institute of Electrical Engineering, Slovak Academy of Sciences, Dúbravska cesta 9, 842 39 Bratislava, Slovakia
2 Institute for Experimental Physics, University of Technology, Vienna, Austria

E-mail: elekkova@savba.sk

Received 12 March 2001, in final form 11 April 2002
Published 21 May 2002

Abstract. Single core MgB2 tape has been made by the powder-in-tube (PIT) method using commercial MgB2 powder (Alfa Aesar ) and two-axial rolling deformation in an Fe/Cu sheath. Transport currents were measured at temperatures 4.2 K-15 K in parallel and perpendicular to the external magnetic field B = 0-5.5 T and at a constant field B = 1 T of variable orientation to the tape surface (0-180°). The transport current anisotropy of the tape with different orientations of the tape surface with respect to the external magnetic field was measured, showing higher currents in perpendicular field orientation. The Ic anisotropy of MgB2 /Fe/Cu tape was observed only for low external fields (0-2.5 T). This behaviour is explained by the Fe sheath magnetization and confirmed by the isotropic behaviour of MgB2/Cu tape prepared by the similar PIT process and by hysteretic Ic(B) curves measured for increased and decreased external field in MgB2/Fe/Cu. The presence of the ferromagnetic barrier in MgB2 composite wire influences the Ic(B) characteristics and may lead to increased hysteretic losses for possible future ac applications.

http://www.iop.org/EJ/S/3/55/abstract/0953-2048/15/7/307/