Ikeda Akihiko, Nomura Toshihiro, Matsuda Yasuhiro H, Tani Shuntaro, Kobayashi Yohei, Watanabe Hiroshi, Sato Keisuke
International MegaGauss Science Laboratory (IMGSL), Institute for Solid State Physics (ISSP), University of Tokyo, Kashiwa, Japan.
Laser and Synchrotron Research Center (LASOR), Institute for Solid State Physics (ISSP), University of Tokyo, Kashiwa, Japan.
Rev Sci Instrum. 2017 Aug;88(8):083906. doi: 10.1063/1.4999452.
A high-speed 100 MHz strain monitor using a fiber Bragg grating, an optical filter, and a mode-locked optical fiber laser has been devised, whose resolution is ΔL/L∼10. The strain monitor is sufficiently fast and robust for the magnetostriction measurements of materials under ultrahigh magnetic fields generated with destructive pulse magnets, where the sweep rate of the magnetic field is in the range of 10-100 T/μs. As a working example, the magnetostriction of LaCoO was measured at room temperature, 115 K, and 7 ∼ 4.2 K up to a maximum magnetic field of 150 T. The smooth dependence on the squared magnetic field and the first-order transition were observed at 115 K and 7 ∼ 4.2 K, respectively, reflecting the field-induced spin state evolution.
已设计出一种使用光纤布拉格光栅、光学滤波器和锁模光纤激光器的高速100 MHz应变监测器，其分辨率为ΔL/L∼10。该应变监测器对于使用破坏性脉冲磁体产生的超高磁场下材料的磁致伸缩测量来说足够快速且稳健，其中磁场的扫描速率在10 - 100 T/μs范围内。作为一个工作示例，在室温、115 K和7 ∼ 4.2 K下测量了LaCoO的磁致伸缩，直至最大磁场为150 T。分别在115 K和7 ∼ 4.2 K观察到对平方磁场的平滑依赖性和一级转变，反映了场诱导的自旋态演化。
