Magnetic Force Sensing Using a Self-Assembled Nanowire

Abstract

We present a scanning magnetic force sensor based on an individual magnet-tipped GaAs nanowire (NW) grown by molecular beam epitaxy. Its magnetic tip consists of a final segment of single-crystal MnAs formed by sequential crystallization of the liquid Ga catalyst droplet. We characterize the mechanical and magnetic properties of such NWs by measuring their flexural mechanical response in an applied magnetic field. Comparison with numerical simulations allows the identification of their equilibrium magnetization configurations, which in some cases include magnetic vortices. To determine a NW's performance as a magnetic scanning probe, we measure its response to the field profile of a lithographically patterned current-carrying wire. The NWs' tiny tips and their high force sensitivity make them promising for imaging weak magnetic field patterns on the nanometer-scale, as required for mapping mesoscopic transport and spin textures or in nanometer-scale magnetic resonance.

Theory of quantum acoustomagnonics and acoustomechanics with a micromagnet

“…10, this measurement is experimentally feasible, especially for acoustic quality factors Q p > 10 7 , as the two peaks reach values ∼ 1pm/Hz 1/2 , even when the center-of-mass motion is only driven by thermal noise. This is within the sensitivity regime of most state-of-the-art ultra-sensitive displacement sensors [79,80,88,90,91,[94][95][96][97][98] and the signal-to-noise ratio in the power spectral density can be largely increased by resonant excitation of the center-of-mass mode. Remarkably, probing the internal modes remains feasible for higher-order acoustic phonons, as evidenced by Fig.…”

Interrelation of Elasticity and Thermal Bath in Nanotube Cantilevers

“…Our measurements are also consistent with the Young's modulus directly computed from a quasiharmonic approximation of the free energy of the phonon modes. This work not only shows how the stiffness of an individual nanotube is related to its phonons, but it also highlights the role of the phonon thermal bath in nanotube cantilevers, which is a topic of importance in the field of nanomechanical resonators [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29].…”

“…In this work, we use the exquisite sensing capabilities of mechanical resonators based on nanoscale systems [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] to resolve the small effect associated with the thermal behavior of their stiffness. Using the resonance frequency measured by optomechanical spectroscopy, we estimate the Young's modulus of micrometer-long nanotube cantilevers from room temperature down to a few Kelvins.…”

Research Progress of Biomimetic Self-assembly of Nanomaterials in Morphology and Performance Control

“…研究纳米尺度自组装为微型电子元器件的制备 提供了技术保障 [63] ，由此得到的电子元器件具有更 高的选择性和灵敏性，能够节约材料，降低成本。 过去几十年里已有大量关于仿生自组装应用于温度 和 pH 传感器 [64][65][66] 、生物和化学传感器 [67][68][69][70] 以及等 离子尺 [71][72][73] 等方面的报道，近年来自组装传感器依 旧是相关领域的研究热点。 Zhang 等 [74] 报道了以柔性聚酰亚胺为衬底(图 9(a) )， 通 过 逐 层 自 组 装 的 方 法 制 备 的 基 于 SnS2/Zn2SnO4 杂化膜柔性湿度传感器，具有响应速 度快、重复性好和室温下稳定性好等优点。不同于 静电纺丝法 [75] 和水热法 [76] 等制备的 Zn2SnO4 化学传 感器(回收率低、室温下灵敏度低) ，自组装法制备 的传感器能够促进 Zn2SnO4 作为气敏元件的应用 [77] 。 Chang 等 [78] 将常规荧光基团芘和吡啶引入配位驱动 的自组装金属环，由此材料的硅支撑薄膜对气态胺 显示出传感特性。 He 等 [79] 通过滑石粉和有机染料分 子的气液界面自组装成膜，研究了自组装复合膜在 不同气体下的颜色可逆变化和气体响应，为功能性 自组装膜的气体传感器和化学开关提供了新的思路。 Rossi 等 [80] 报道了用于磁力传感器的自组装 GaAs 纳米线， 与传统方法获得的机械力传感器相比 尺寸更小，灵敏度 [81] 和分辨率 [82] 更高。有研究团 队采用不同自组装基元制备了多种类型的传感器， 如用于电子皮肤和可穿戴传感器等的石墨烯应力传 感器 [83] (图 9(c))，荧光有机纳米粒子铁(Ⅲ)传感 器 [84] ，灵活的葡萄糖生物传感器 [85] (图 9(b))，以及 用于特定氨基酸电化学识别的手性传感装置 [86] 等。…”