Magnetic relaxation induced by transverse flux shaking in MgB2 superconductors

J. LUZURIAGA; A. BADÍA-MAJÓS; G. NIEVA; J. L. GIORDANO; C. LÓPEZ; A. SERQUIS; G. SERRANO

SUPERCONDUCTOR SCIENCE AND TECHNOLOGY

IOP PUBLISHING LTD

Año: 2009 vol. 22 p. 150211 - 150216

0953-2048

We report on measurements and numerical simulations of the behavior of MgB2superconductors when magnetic field components are applied along mutually perpendiculardirections. By closely matching the geometry in simulations and measurements, fullquantitative agreement is found. The critical state theory and a single phenomenological law,i.e. the field dependence of the critical current density Jc(B), are sufficient for a full quantitativedescription of the measurements. These were performed in thick strips of carbon nanotubedoped MgB2 samples. Magnetization was measured in two orthogonal directions using aSQUID magnetometer. Magnetic relaxation effects induced by the application of an oscillatoryperpendicular field were observed and simulated numerically. The measurements confirm thenumerical predictions, that two relaxation regimes appear, depending on the amplitude of theapplied magnetic field. The overall agreement constitutes a convincing validation of the criticalstate model and the numerical procedures used.