Experimental research on the residual magnetization of a rare-earth permanent magnet for a cryogenic undulator

Abstract

The magnetic properties of commercial polycrystalline Nd2Fe14B (N50M, N45H, N40SH, N35EH) and Sm2Co17 (XG30/20, XG26/25, XG22/20) magnets at cryogenic temperatures were tested by using a comprehensive physical properties measurement system (PPMS). The results show that the spin tilt temperature Tst of Nd2Fe14B magnets is closely related to intrinsic coercivity Hci, N50M and N45H with smaller Hci show a residual magnetization jump at 235 K and 225 K, respectively. For Sm2Co17 magnets, in 50–300 K, with temperature decreasing, residual magnetization Mrc shows a nearly linear increase, while in 10–50 K, Mrc has little change. The research results provide a reference for cryogenic undulators and other high-precision cryogenic devices.