Huang Haiming, Shuai Mingming, Yang Yulong, Song Rui, Liao Yanghui, Yin Lifeng, Shen Jian
State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China.
Rev Sci Instrum. 2022 Jul 1;93(7):073703. doi: 10.1063/5.0095271.
Spin polarized scanning tunneling microscopy (SP-STM) and magnetic exchange force microscopy (MExFM) are powerful tools to characterize spin structure at the atomic scale. For low temperature measurements, liquid helium cooling is commonly used, which has the advantage of generating low noise but has the disadvantage of having difficulties in carrying out measurements with long durations at low temperatures and measurements with a wide temperature range. The situation is just reversed for cryogen-free STM, where the mechanical vibration of the refrigerator becomes a major challenge. In this work, we have successfully built a cryogen-free system with both SP-STM and MExFM capabilities, which can be operated under a 9 T magnetic field provided by a cryogen-free superconducting magnet and in a wide temperature range between 1.4 and 300 K. With the help of our specially designed vibration isolation system, the noise is reduced to an extremely low level of 0.7 pm. The Fe/Ir(111) magnetic skyrmion lattice is used to demonstrate the technical novelties of our cryogen-free system.
自旋极化扫描隧道显微镜（SP-STM）和磁交换力显微镜（MExFM）是在原子尺度表征自旋结构的强大工具。对于低温测量，通常使用液氦冷却，其优点是产生低噪声，但缺点是在低温下进行长时间测量以及在宽温度范围内测量存在困难。对于无液氦STM，情况则正好相反，此时制冷机的机械振动成为主要挑战。在这项工作中，我们成功构建了一个兼具SP-STM和MExFM功能的无液氦系统，该系统可以在由无液氦超导磁体提供的9 T磁场下以及在1.4至300 K的宽温度范围内运行。借助我们专门设计的隔振系统，噪声降低到极低的0.7 pm水平。利用Fe/Ir(111)磁性斯格明子晶格来展示我们无液氦系统的技术新颖性。
