Poster (Scientific congresses and symposiums)
Decay of the axial magnetization of GdBCO pellets subjected to small transverse alternating magnetic fields.
Fagnard, Jean-François; Kirsch, Sébastien; Teshima, Hidekazu et al.
2013EUropean Conference on Applied Superconductivity EUCAS 2013
 

Files


Full Text
Poster_Eucas2013_JFF_01.pdf
Author postprint (280.14 kB)
Request a copy

All documents in ORBi are protected by a user license.

Send to



Details



Keywords :
Bulk superconductors; Crossed fields
Abstract :
[en] Bulk (RE)BCO materials (where RE denotes a rare-earth ion) are known to be used as strong permanent magnets in various engineering devices, such as magnetic bearings or rotating machines. In so doing, the bulk pellet is usually magnetized along its c-axis and a permanent magnetic moment is trapped. In real application, however, the pellet is likely to be subjected to small parasitic magnetic fields that cause a decay of the permanent magnetic moment. The most severe effects arise when the pellets are subjected to ac magnetic field cycles that are perpendicular to their c- axis (“crossed-fields” configuration). Our previous works relate to a small number of transverse cycles of large amplitude. In the present work we consider a large number (> 10^4) of cycles of small amplitude, which is closer to practical situations. The study is carried out on bulk single grain GdBCO pellet. The samples are two 10 mm height and 15 mm diameter cylinders, one of which is surrounded by a 2 mm thick stainless steel reinforcement ring. The transverse field is sinusoidal, its frequency ranges between 10 Hz and 800 Hz and its amplitude ranges between 5 mT and 50 mT. The resulting decay of the axial magnetization of the samples is recorded against time and flux-creep effects are subtracted. Thermocouples are placed at several locations on the samples surface to probe possible heating. For these small amplitudes of the magnetic field, corresponding to only few percents of the penetration field, results show that the magnetization decay depends mainly on the time during which the transverse field is applied. This is in contrast with results obtained at larger amplitudes of the magnetic field and for which the decay is linked to the number of cycles. We also show that the natural relaxation of the axial magnetization is strongly affected or even suppressed after a short time exposition to the transverse ac magnetic field. Acknowledgements We thank the FRS-FNRS, the Communauté Française de Belgique for cryofluid, travel and equipment grants, under reference ARC 11/16-03.
Research center :
SUPRATECS - Services Universitaires pour la Recherche et les Applications Technologiques de Matériaux Électro-Céramiques, Composites, Supraconducteurs - ULiège
Disciplines :
Physics
Electrical & electronics engineering
Author, co-author :
Fagnard, Jean-François  ;  Université de Liège - ULiège > Dép. d'électric., électron. et informat. (Inst.Montefiore) > Capteurs et systèmes de mesures électriques
Kirsch, Sébastien;  Université de Liège - ULiège > Dép. d'électric., électron. et informat. (Inst.Montefiore) > Electronique et microsystèmes
Teshima, Hidekazu;  Nippon Steel & Sumitomo Metal Corporation, Futtsu, Chiba 293-8511, Japan
Morita, Mitsuru;  Nippon Steel & Sumitomo Metal Corporation, Futtsu, Chiba 293-8511, Japan
Vanderheyden, Benoît  ;  Université de Liège - ULiège > Dép. d'électric., électron. et informat. (Inst.Montefiore) > Electronique et microsystèmes
Vanderbemden, Philippe  ;  Université de Liège - ULiège > Dép. d'électric., électron. et informat. (Inst.Montefiore) > Capteurs et systèmes de mesures électriques
Language :
English
Title :
Decay of the axial magnetization of GdBCO pellets subjected to small transverse alternating magnetic fields.
Publication date :
September 2013
Event name :
EUropean Conference on Applied Superconductivity EUCAS 2013
Event place :
Genoa, Italy
Event date :
Du 16 au 19 septembre 2013
Audience :
International
Name of the research project :
SUPERCOOL - ARC 11/06-03
Funders :
F.R.S.-FNRS - Fonds de la Recherche Scientifique [BE]
Available on ORBi :
since 16 November 2017

Statistics


Number of views
26 (4 by ULiège)
Number of downloads
0 (0 by ULiège)

Bibliography


Similar publications



Contact ORBi