Scanning probe microscopy in an ultra-low vibration closed-cycle cryostat

Abstract

We report on state-of-the-art scanning probe microscopy measurements performed in a pulse tube based top-loading closed-cycle cryostat with a base temperature of 4 K and a 9 T magnet. We decoupled the sample space from the mechanical and acoustic noise from the cryocooling system to enable scanning probe experiments. The extremely low vibration amplitudes in our system enabled successful imaging of 0.39 nm lattice steps on single crystalline SrTiO$_{3}$ as well as magnetic vortices in Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+x}$ superconductor. Fine control over sample temperature and applied magnetic field further enabled us to probe the helimagnetic and the skyrmion-lattice phases in Fe$_{0.5}$Co$_{0.5}$Si with unprecedented signal-to-noise ratio of 20:1. Finally, we demonstrate for the first time quartz-crystal tuning fork shear-force microscopy in a closed-cycle cryostat.