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A new MgB2 bulk ring fabrication technique for use in magnetic shielding or bench-top NMR systems

Accepted version
Peer-reviewed

Type

Article

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Authors

Wilkinson, Daniel 
Mousavi, Tayebeh 
Dennis, Anthony R 
Speller, Susannah C  ORCID logo  https://orcid.org/0000-0002-6497-5996

Abstract

jats:titleAbstract</jats:title> jats:pWe report a new methodology in bulk MgBjats:sub2</jats:sub> ring production for use in small-scale magnetic shielding or bench-top NMR systems. This process is a modified field-assisted sintering technique (mFAST) which enables direct formation of the rings without the need for machining or additives into the precursor powder. The shielding and trapped field capabilities of three mFAST MgBjats:sub2</jats:sub> rings were determined using zero-field- (ZFC) and field-cooled (FC) magnetic experiments. Individual bulks trap magnetic fields up to 1.24T at 20K comparable to the highest published data for a ring sample. It is anticipated that for many applications, multiple rings will be stacked to form the required experimental structure. We find for the three ring stack a trapped field of 2.04T and a maximum shielded field of 1.74T at 20K. The major factor limiting performance at low temperatures are flux jumps which cause rapid loss of the trapped field or shielding capability. Preliminary studies of magnetic field ramp rate dependence on flux jumps were conducted illustrating that even at very slow ramp rates (0.007 T/min) they remain a significant issue. Despite this concern, we conclude that mFAST represents an exciting new fabrication methodology for bulk MgBjats:sub2</jats:sub> rings.</jats:p>

Description

Keywords

Journal Title

Superconductor Science and Technology

Conference Name

Journal ISSN

0953-2048
1361-6668

Volume Title

Publisher

IOP Publishing
Sponsorship
Engineering and Physical Sciences Research Council (EP/P023088/1)
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