IMR: Development of a Variable Temperature/Variable Magnetic Field Scanning Force Microscope and Student Training

我们建议开发一种变温度、变磁场的超高真空扫描力显微镜，使局部测量摩擦力、静磁力和静电力作为温度（10 K ~ 300 K）和磁场（B 0.1 T）的函数。新仪器将把经过良好测试的元素与以前未应用于SFM的新设计元素结合在一起。极高的分辨率和稳定性，超高真空的原位尖端和样品制备，从10 K到室温的温度灵活性，以及高达0.1 T以上的磁场，在美国将是独一无二的。过去，人们已经在纳米尺度上探索了摩擦作为施加载荷或滑动速度的函数，但由于缺乏合适的设备，很少有研究将摩擦作为温度的函数。这样的实验将有助于测试当前的摩擦理论模型，这些模型将摩擦描述为一个热激活的过程。为了解决这些问题，我们将研究摩擦作为温度的函数，并测量相变时的摩擦，以分离声子和电子对摩擦的贡献。在本项目中，我们将使用静电力显微镜和磁力显微镜在不同温度和磁场下对巨磁阻（CMR）锰矿石中共存的铁磁性金属团簇和电荷有序绝缘团簇之间的相分离进行局部成像。我们还将使用电场效应方法研究外延铁电/CMR异质结构相渗透的低场操纵。在这个实验中，我们将寻求通过施加小电压（几伏）在低磁场（数百高斯）下诱导金属导电。我们建议开发一种变温度、变磁场的超高真空扫描力显微镜，使局部测量摩擦力、静磁力和静电力作为温度和磁场的函数。新仪器将把经过良好测试的元素与以前没有应用过的新设计元素结合在一起。超高分辨率和稳定性、超高真空、原位尖端和样品制备、温度灵活性和高达0.1 T以上的磁场等特性在美国是独一无二的。过去，人们已经在纳米尺度上探索了摩擦作为施加载荷或滑动速度的函数，但由于缺乏合适的设备，很少有研究将摩擦作为温度的函数。这样的实验将有助于测试当前的摩擦理论模型，这些模型将摩擦描述为一个热激活的过程。

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.