IPAC2014 - List of Authors (Brombacher, C.)

Paper	Title	Page
TUPRO085	Properties, Options and Limitations of PrFeB-magnets for Cryogenic Undulators	1238
	F.-J. Börgermann, C. Brombacher, K. Üstüner Vacuumschmelze GmbH & Co. KG, Hanau, Germany
	The gap induction and thus the K-factor of permanent magnet undulators may be increased by cooling them to cryogenic temperatures. The use of NdFeB-magnets in cryogenic undulators, however, is limited to temperatures above 140 K due to the spin-reorientation transition (SRT) which leads to a reduction of the magnetization level. A further increase of the gap induction in undulators may be achieved by use of PrFeB-magnets at even lower temperatures, as this alloy does not show the SRT phenomenon. Although the effects are well known, up to now only a few undulator prototypes were built using this class of material since the coercivity of ternary PrFeB-magnets is not sufficient to minimize the risk of partial demagnetization when the undulator structure is kept at room temperature. This problem can be solved by applying actual technologies like grain-boundary diffusion in order to achieve coercivities exceeding 20 kOe at RT without sacrificing the high remanence Br of about 1.6 T at 77 K. We will provide actual data of the magnet performance achieved and show up the technological limitations in building PrFeB-based CPMU’s.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO085
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Paper

Title

Page

Properties, Options and Limitations of PrFeB-magnets for Cryogenic Undulators

1238

F.-J. Börgermann, C. Brombacher, K. Üstüner
Vacuumschmelze GmbH & Co. KG, Hanau, Germany

The gap induction and thus the K-factor of permanent magnet undulators may be increased by cooling them to cryogenic temperatures. The use of NdFeB-magnets in cryogenic undulators, however, is limited to temperatures above 140 K due to the spin-reorientation transition (SRT) which leads to a reduction of the magnetization level. A further increase of the gap induction in undulators may be achieved by use of PrFeB-magnets at even lower temperatures, as this alloy does not show the SRT phenomenon. Although the effects are well known, up to now only a few undulator prototypes were built using this class of material since the coercivity of ternary PrFeB-magnets is not sufficient to minimize the risk of partial demagnetization when the undulator structure is kept at room temperature. This problem can be solved by applying actual technologies like grain-boundary diffusion in order to achieve coercivities exceeding 20 kOe at RT without sacrificing the high remanence Br of about 1.6 T at 77 K. We will provide actual data of the magnet performance achieved and show up the technological limitations in building PrFeB-based CPMU’s.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO085

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)