A low temperature ultrahigh vaccum scanning force microscope

This article describes the design of a versatile ultrahigh vaccum (UHV) low temperature scanning force microscope system. The system allows scanning probe microscopy measurements at temperatures between 6 and 400 K and in magnetic fields up to 7 T. Cantilevers and samples can be prepared in UHV and transferred to the microscope. We describe some technical details of our system and present first measurements performed at different temperatures and in various scanning force microscopy operation modes. We demonstrate distortion free and calibrated images at temperatures ranging from 8 to 300 K, atomic resolution on NaCl at 7.6 K and various magnetic force microscopy images of vortices in high transition temperature superconductors. It is demonstrated that our instrumentation reaches the thermodynamically determined sensitivity limit. Using standard cantilevers force gradients in the 10(-6)N/m range, corresponding forces of about 10(-15)N can be measured. (C) 1999 American Institute of Physics. [S0034-6748(99)00909-0].