Trapped Fields >1 T in a Bulk Superconducting Ring by Pulsed Field Magnetization

TY - JOUR

T1 - Trapped Fields >1 T in a Bulk Superconducting Ring by Pulsed Field Magnetization

AU - Tsui, Yee Kin

AU - Moseley, Dominic A.

AU - Dennis, Anthony R.

AU - Shi, Yun Hua

AU - Beck, Michael R.

AU - Cientanni, Vito

AU - Cardwell, David A.

AU - Durrell, John H.

AU - Ainslie, Mark D.

N1 - Funding Information: This work was supported in part by the Engineering and Physical Sciences Research Council Early Career Fellowship under Grant EP/P020313/1, and in part by the EPSRC under Grant EP/T014679/1 Publisher Copyright: © 2002-2011 IEEE.

PY - 2022/3/18

Y1 - 2022/3/18

N2 - One potential application of magnetized RE-Ba-Cu-O (where RE = rare earth or Y) bulk superconductors is as a high-field alternative to conventional permanent magnets in desktop NMR and MRI systems. Pulsed field magnetization (PFM) is one of the most promising practical methods of magnetizing such bulks. However, the trapped fields obtained by PFM are much lower than those obtained using quasi-static methods like field-cooling magnetization (FCM) due to heating during PFM. Furthermore, bulk superconducting rings have proved more difficult to magnetize via PFM than discs. The reported trapped fields in single bulk superconducting rings magnetized by PFM are less than 0.35 T at the centre of the bore due to thermomagnetic instabilities. In this work, systematic PFM measurements on a bulk Gd-Ba-Cu-O ring were carried out and a trapped field of 1.3 T at 55 K was achieved using a multi-pulse, stepwise cooling (MPSC) method. In the MPSC method, a sequence of pulsed fields is used to magnetize the ring bulk. The pulsed field is increased in small increments and the sample temperature is decreased sequentially. Consequently, as some field is already trapped after the first pulse, the motion of the flux for subsequent pulses will be reduced, leading to less heat generated in the bulk sample. This greatly improves the thermomagnetic stability of the PFM process, enabling larger trapped fields.

AB - One potential application of magnetized RE-Ba-Cu-O (where RE = rare earth or Y) bulk superconductors is as a high-field alternative to conventional permanent magnets in desktop NMR and MRI systems. Pulsed field magnetization (PFM) is one of the most promising practical methods of magnetizing such bulks. However, the trapped fields obtained by PFM are much lower than those obtained using quasi-static methods like field-cooling magnetization (FCM) due to heating during PFM. Furthermore, bulk superconducting rings have proved more difficult to magnetize via PFM than discs. The reported trapped fields in single bulk superconducting rings magnetized by PFM are less than 0.35 T at the centre of the bore due to thermomagnetic instabilities. In this work, systematic PFM measurements on a bulk Gd-Ba-Cu-O ring were carried out and a trapped field of 1.3 T at 55 K was achieved using a multi-pulse, stepwise cooling (MPSC) method. In the MPSC method, a sequence of pulsed fields is used to magnetize the ring bulk. The pulsed field is increased in small increments and the sample temperature is decreased sequentially. Consequently, as some field is already trapped after the first pulse, the motion of the flux for subsequent pulses will be reduced, leading to less heat generated in the bulk sample. This greatly improves the thermomagnetic stability of the PFM process, enabling larger trapped fields.

KW - bulk superconducting rings

KW - Bulk superconductors

KW - high-temperature superconductivity

KW - multi-pulse stepwise cooling

KW - pulsed field magnetization

KW - trapped field magnets

KW - waveform control

UR - http://www.scopus.com/inward/record.url?scp=85126668403&partnerID=8YFLogxK

U2 - 10.1109/TASC.2022.3160661

DO - 10.1109/TASC.2022.3160661

M3 - Article

AN - SCOPUS:85126668403

SN - 1051-8223

VL - 32

JO - IEEE Transactions on Applied Superconductivity

JF - IEEE Transactions on Applied Superconductivity

IS - 6

M1 - 6800905

ER -