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

我们提出了一种变温、变磁场的超高真空扫描力显微镜的研制，它能够局部测量摩擦力、静磁力和静电力随温度(10K T 300K)和磁场(B0.1T)的变化。新仪器将把经过良好测试的元素与以前从未应用于SFM的新设计元素结合在一起。极高的分辨率和稳定性，具有原位针尖和样品制备的超高真空，从10K到室温的温度灵活性，以及高达0.1T的磁场将是美国独一无二的。过去，摩擦作为施加的载荷或滑动速度的函数在纳米尺度上进行了研究，但由于缺乏合适的设备，作为温度函数的研究很少。这些实验将有助于检验当前的摩擦理论模型，这些模型将摩擦描述为一个热激活过程。为了解决这些问题，我们将研究摩擦力作为温度的函数，并测量相变时的摩擦力，以便区分声子和电子对摩擦力的贡献。在这个项目中，我们将使用静电力显微镜和磁力显微镜在不同的温度和磁场下对共存于巨磁电阻(CMR)锰氧化物中的铁磁金属和电荷有序绝缘团簇之间的相分离进行局部成像。我们还将用电场效应的方法研究外延铁电/CMR异质结的相渗流的低场操控。在这个实验中，我们将通过施加小电压(几伏)来观察在低磁场(数百高斯)下感应金属导电。我们建议开发一种变温、变磁场的超高真空扫描力显微镜，它能够局部测量摩擦力、静磁力和静电力随温度和磁场的变化。新仪器将把经过良好测试的元素与以前从未应用过的新设计元素结合在一起。极高的分辨率和稳定性、具有原位针尖和样品制备的超高真空、温度灵活性以及高达0.1T的磁场将是美国独一无二的。过去，摩擦作为施加的载荷或滑动速度的函数在纳米尺度上进行了研究，但由于缺乏合适的设备，作为温度函数的研究很少。这些实验将有助于检验当前的摩擦理论模型，这些模型将摩擦描述为一个热激活过程。

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.