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We developed a process to fabricate nanoscale metallic gate electrodes on scanning probe cantilevers, including on the irregular surface of protruding cantilever tips. The process includes a floating-layer technique to coat the cantilevers in an electron-beam resist. We demonstrate gate definition through a lift-off process and through an etching process. The cantilevers maintain a high force sensitivity after undergoing the patterning process. Our method allows the patterning of nanoscale devices on fragile scanning probes, extending their functionality as sensors. [ABSTRACT FROM AUTHOR]

We report nonlinear behavior in the motion of driven nanowire cantilevers. The nonlinearity can be described by the Duffing equation and is used to demonstrate mechanical mixing of two distinct excitation frequencies. Furthermore, we demonstrate that the nonlinearity can be used to amplify a signal at a frequency close to the mechanical resonance of the nanowire oscillator. Up to 26 dB of amplitude gain is demonstrated in this way. [ABSTRACT FROM AUTHOR]

Recent advances in the fabrication of microelectromechanical systems and their evolution into nanoelectromechanical systems have enabled researchers to measure extremely small forces, masses and displacements. In particular, researchers have developed position transducers with resolution approaching the uncertainty limit set by quantum mechanics. The achievement of such resolution has implications not only for the detection of quantum behaviour in mechanical systems, but also for a variety of other precision experiments including the bounding of deviations from newtonian gravity at short distances and the measurement of single spins. Here, we demonstrate the use of a quantum point contact as a sensitive displacement detector capable of sensing the low-temperature thermal motion of a nearby micromechanical cantilever. Advantages of this approach include versatility due to its off-board design, compatibility with nanoscale oscillators and, with further development, the potential to achieve quantum-limited displacement detection. [ABSTRACT FROM AUTHOR]

Frequency domain multiplexing, using an actively damped micromechanical cantilever, is used to detect multiple force signals simultaneously. The measurement principle is applied to magnetic resonance force microscopy to allow concurrent measurement of nuclear spin signals originating from distinct regions of the sample, or from multiple spin species. [ABSTRACT FROM AUTHOR]

The authors use a 1.0 μm wide patterned Cu wire with an integrated nanomagnetic tip to measure the statistical nuclear polarization of 19F in CaF2 by magnetic resonance force microscopy. With less than 350 μW of dissipated power, the authors achieve rf magnetic fields over 4 mT at 115 MHz for a sample positioned within 100 nm of the “microwire” rf source. A 200 nm diameter FeCo tip integrated onto the wire produces field gradients greater than 105 T/m at the same position. The large rf fields from the broadband microwire enable long rotating-frame spin lifetimes of up to 15 s at 4 K. [ABSTRACT FROM AUTHOR]

We use a quantum point contact (QPC) as a displacement transducer to measure and control the low-temperature thermal motion of a nearby micromechanical cantilever. The QPC is included in an active feedback loop designed to cool the cantilever's fundamental mechanical mode, achieving a squashing of the QPC noise at high gain. The minimum achieved effective mode temperature of 0.2 K and the displacement resolution of [formula] are limited by the performance of the QPC as a one-dimensional conductor and by the cantilever-QPC capacitive coupling. [ABSTRACT FROM AUTHOR]

Usingdynamic cantilever magnetometry we measure an enhanced skyrmion latticephase extending from around 29 K down to at least 0.4 K in singleMnSi nanowires (NWs). Although recent experiments on two-dimensionalthin films show that reduced dimensionality stabilizes the skyrmionphase, our results are surprising given that the NW dimensions aremuch larger than the skyrmion lattice constant. Furthermore, the stabilityof the phase depends on the orientation of the NWs with respect tothe applied magnetic field, suggesting that an effective magneticanisotropy, likely due to the large surface-to-volume ratio of thesenanostructures, is responsible for the stabilization. The compatibilityof our technique with nanometer-scale samples paves the way for futurestudies on the effect of confinement and surfaces on magnetic skyrmions. [ABSTRACT FROM AUTHOR]

Nanoscale magnets might form the building blocks of next generation memories. To explore their functionality, magnetic sensing at the nanoscale is key. We present a multifunctional combination of a nanometer-sized superconducting quantum interference device (nanoSQUID) and a Ni nanotube attached to an ultrasoft cantilever as a magnetic tip. By scanning the Nb nanoSQUID with respect to the Ni tube, we map out and analyze their magnetic coupling, demonstrate the imaging of an Abrikosov vortex trapped in the SQUID structure ― which is important in ruling out spurious magnetic signals ― and reveal the high potential of the nanoSQUID as an ultrasensitive displacement detector. Our results open a new avenue for fundamental studies of nanoscale magnetism and superconductivity. [ABSTRACT FROM AUTHOR]