We propose the development of a variable temperature, variable magnetic field ultrahigh vacuum scanning force microscope that enables the local measurement of frictional, magnetostatic, and electrostatic forces as a function of temperature (10 K < T < 300 K) and magnetic field (B < 0.1 T). The new instrument will combine well-tested elements together with new design elements that have not been applied to SFM before. The attributes of extremely high resolution and stability, ultrahigh vacuum with in-situ tip and sample preparation, flexibility in temperature from 10 K to room temperature, and magnetic fields up to more than 0.1 T would be unique in the US. Friction has been explored at the nanoscale in the past as a function of the applied load or the sliding velocity, but very little has been done as a function of the temperature due to a lack of suitable equipment. Such experiments will be useful to test current theoretical models of friction, which describe friction as a thermally activated process. To address these questions, we will investigate friction as a function of the temperature, and also measure friction at phase transitions in order to separate phononic and electronic contributions to friction. In this project, we will carry out local imaging of the phase separation between ferromagnetic metallic and charge-ordered insulating clusters that coexist in colossal magnetoresistive (CMR) manganites using electrostatic force microscopy and magnetic force microscopy at variable temperatures and magnetic fields. We will also examine the low field manipulation of phase percolation of epitaxial ferroelectric/CMR heterostructures using an electric field effect approach. In this experiment, we will look to induce metallic conduction at low magnetic fields (hundreds of gauss) by applying small voltages (a few volts). %%% We propose the development of a variable temperature, variable magnetic field ultrahigh vacuum scanning force microscope that enables the local measurement of frictional, magnetostatic, and electrostatic forces as a function of temperature and magnetic field. The new instrument will combine well-tested elements together with new design elements that have not been applied before. The attributes of extremely high resolution and stability, ultrahigh vacuum with in-situ tip and sample preparation, flexibility in temperature, and magnetic fields up to more than 0.1 T would be unique in the US. Friction has been explored at the nanoscale in the past as a function of the applied load or the sliding velocity, but very little has been done as a function of the temperature due to a lack of suitable equipment. Such experiments will be useful to test current theoretical models of friction, which describe friction as a thermally activated process.
