上海光源低温波荡器永磁铁在低温下的磁特性研究

摘要

M-H and M-T curve at cryogenic (10–300 K) of domestic Nd2Fe14B (N50M) permanent magnet are tested by physical property measurement system (PPMS). Br-T and Hci-T figure under the cryogenic condition for N50M are obtained. The orientation degree and three-dimensional magnetization are also analyzed and researched under the cryogenic conditon. The results show that N50M has a strong spin reorientation effect(SRT) between 80 and 150 K, Br shows a peak between 120 and 130 K and Hci increases linearly with temperature decresing. At 130 K, Br increases 15.6% and Hci increases 220% compared with at room temperature (300 K), reaching 1.65 T and 3638 kA/m respectively. Between 150 and 300 K, with temperature declining, the macroscopic orientation degree uniformity and the external magnetic field uniformity of N50M are improved gradually. Between 80 and 235 K, the micro-external magnetic field uniformity shows a deterioration phenomenon. The experimental research also indicates that near 235 K the N50M perpendicular to orientation direction presents a“remanent magnetization jump”phenomenon. The experimental results provide a reference for the physical design of cryogenic undulator for Shanghai Synchrotron Radiation Facility II and other high-precision cryogenic permanent magnet instruments and equipment.%　　用综合物性测量系统测试了国产Nd2Fe14B (N50M)永磁铁在低温下(10—300 K)的M-H 和M-T.获得了N50M剩磁Br和内禀矫顽力Hci在低温下的变化图,对其取向度和三维磁化强度进行了分析研究.结果表明, N50M在80—150 K发生强烈自旋再取向效应, Br在120—130 K出现峰值, Hci随温度下降呈线性增加.在130 K, Br和Hci分别比常温(300 K)增加15.6%和220%,达到1.65 T和3638 kA/m.在150—300 K,随温度下降, N50M宏观取向度与外磁场均匀性逐步改善,但在80—235 K,微观外磁场均匀性恶化.实验研究发现,235 K附近, N50M垂直取向方向呈现“剩余磁化强度跳跃”.研究结果为上海光源II期低温波荡器及其他高精度低温永磁仪器与设备的物理设计提供了参考.