Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853-1301, USA.
ACS Nano. 2010 Dec 28;4(12):7141-50. doi: 10.1021/nn101577t. Epub 2010 Nov 17.
We have batch-fabricated cantilevers with ∼100 nm diameter nickel nanorod tips and force sensitivities of a few attonewtons at 4.2 K. The magnetic nanorods were engineered to overhang the leading edge of the cantilever, and consequently the cantilevers experience what we believe is the lowest surface noise ever achieved in a scanned probe experiment. Cantilever magnetometry indicated that the tips were well magnetized, with a ≤ 20 nm dead layer; the composition of the dead layer was studied by electron microscopy and electron energy loss spectroscopy. In what we believe is the first demonstration of scanned probe detection of electron-spin resonance from a batch-fabricated tip, the cantilevers were used to observe electron-spin resonance from nitroxide spin labels in a film via force-gradient-induced shifts in cantilever resonance frequency. The magnetic field dependence of the magnetic resonance signal suggests a nonuniform tip magnetization at an applied field near 0.6 T.
我们批量制造了具有约 100nm 直径镍纳米棒尖端的悬臂梁，在 4.2K 时的力灵敏度为几个阿特牛顿。磁性纳米棒被设计为悬于悬臂梁的前缘，因此悬臂梁经历了我们认为在扫描探针实验中从未达到过的最低表面噪声。悬臂梁磁强计表明，尖端具有良好的磁化，其死层厚度≤20nm；通过电子显微镜和电子能量损失光谱研究了死层的组成。在我们认为的首次批量制造的尖端扫描探针检测电子自旋共振的演示中，通过悬臂梁共振频率的力梯度诱导位移，使用悬臂梁观察到薄膜中氮氧自由基自旋标记的电子自旋共振。磁共振信号的磁场依赖性表明，在接近 0.6T 的外加磁场下，尖端的磁化不均匀。
