XYZ on a Chip: Magnetic Nanosensors on a Chip

cleland PI最近开发了一种方法，通过这种方法，可以制造深度亚微米尺寸的机械结构，集成位移诱导和位移传感元件，并将其用作实用的传感器。PI希望将这项技术应用于基于芯片的高频磁传感器的开发，这种传感器最终将对单个磁矩的行为敏感。他们将开发的传感器将基于纳米尺度的射频悬臂，由单晶砷化镓异质结构衬底制成。砷化镓是一种压电材料，允许使用压阻和压电应变传感。磁性信号要么来自嵌入在传感器几何结构中的磁性样品，要么来自集成在悬臂设计中的磁性尖端的相互作用，该尖端被扫描在固定的磁性活性样品上。在前一种几何结构中，他们计划进行实验来探测非常小的铁磁和顺磁样品的物理特性，以及光诱导电子和核磁化的机械检测。后一种几何形状将允许许多显微镜应用，探测表面和地下的相互作用。从地下源发出的信号，如埋藏异质结构界面上的电流，将允许在没有拓扑特征的样品上成像。与目前最先进的扫描磁力探头和固定转矩磁力计相比，这些传感器应该能够探测时间尺度缩短约4个数量级，磁体积尺度缩小约5个数量级。在接近1ghz的频率下，这些传感器的灵敏度应该达到一阶玻尔磁子。高频率和小的物理尺寸尺度，他们将因此能够探测将产生许多有趣的工程和科学应用

9980734ClelandThe PI's have recently developed methods by which deep sub-micron-size mechanical structures, with integrated displacement-inducing and displacement-sensing elements, can be fabricated and used as practical sensors. The PI's wish to apply this technology to the development of high-frequency chip-based magnetic sensors, which in the ultimate limit will be sensitive to the behavior of individual magnetic moments. The sensors they will develop will be based on nanometer-scale, radiofrequency cantilevers, fabricated from single-crystal GaAs heterostructure substrates. GaAs is a piezoelectric material, allowing the use of both piezoresistive and piezoelectric strain sensing. The magnetic signals will emanate either from magnetic samples embedded in the sensor geometry, or from the interaction of an magnetic tip integrated in the cantilever design, which is scanned over a fixed, magnetically active sample. In the former geometry, they plan experiments to probe the physics of very small ferromagnetic and paramagnetic samples, and the mechanical detection of optically-induced electronic and nuclear magnetization. The latter geometry will allow a number of microscopy applications, probing both surface and subsurface interactions. Signals emanating from subsurface sources, such as electric currents on a buried heterostructure interface, would allow imaging on an otherwise topologically featureless sample.These sensors should be able to probe time scales approximately four orders of magnitude shorter, and magnetic volume scales approximately five orders of magnitude smaller, than the present state-of-the-art in scanned magnetic force probes and fixed torque magnetometry. These sensors should allow sensitivities of order one Bohr magneton at frequencies approaching 1 GHz. The high frequencies and small physical size scales they will thereby be able to probe will engender a number of interesting engineering and science applications.***