A M was supported by the King Abdullah University of Science and Technology (KAUST) T J acknowledges support from the EU FET Open RIA Grant No 766566, the Ministry of Education of the Czech Republic Grant No LM2015087 and LNSM-LNSpin, and the Grant Agency of the Czech Republic Grant No 19-28375X J S acknowledges the Alexander von Humboldt Foundation, EU FET Open Grant No 766566, EU ERC Synergy Grant No 610115, and the Transregional Collaborative Research Center (SFB/TRR) 173 SPIN+X K G and P G acknowledge stimulating discussions with C O Avci and financial support by the Swiss National Science Foundation (Grants No 200021-153404 and No 200020-172775) and the European Commission under the Seventh Framework Program (spOt project, Grant No 318144) A T acknowledges support by the Agence Nationale de la Recherche, Project No ANR-17-CE24-0025 (TopSky) J Ž acknowledges the Grant Agency of the Czech Republic Grant No 19-18623Y and support from the Institute of Physics of the Czech Academy of Sciences and the Max Planck Society through the Max Planck Partner Group programme

/pdf/current-induced-spin-orbit-torques-in-ferromagnetic-and-3tdt106r3u.pdf

Current-induced spin-orbit torques in ferromagnetic and antiferromagnetic systems

With an optical interferometer, the free vibration spectra and the local vibration amplitude of four rectangular atomic force microscope cantilevers made of silicon have been examined experimentally in a spectral range of 100 kHz to 10 MHz. A good agreement with the flexural wave theory of elastic beams was found. Coupling to torsional vibrations was also observed. When the sensor tip of the cantilever is in contact with a sample surface the resonances are shifted in frequency and the vibration amplitudes along the cantilever change. A method is presented to calculate this frequency shift using a linear approximation for the tip–sample interaction forces, and the results are compared with the frequency shift calculated from the point‐mass model. The measured resonance frequencies of a surface‐coupled cantilever do not correspond as well to the theoretical ones as in the free case even if the elastic‐beam model is used. The reason for the disagreement is found to be the geometry of the commercial cantileve...

Vibrations of free and surface‐coupled atomic force microscope cantilevers: Theory and experiment

Control can enable high-bandwidth nanopositioning needed to increase the operating speed of scanning probe microscopes (SPMs). High-speed SPMs can substantially impact the throughput of a wide range of emerging nanosciences and nanotechnologies. In particular, inversion-based control can find the feedforward input needed to account for the positioning dynamics and, thus, achieve the required precision and bandwidth. This article reviews inversion-based feedforward approaches used for high-speed SPMs such as optimal inversion that accounts for model uncertainty and inversion-based iterative control for repetitive applications. The article establishes connections to other existing methods such as zero-phase-error-tracking feedforward and robust feedforward. Additionally the article reviews the use of feedforward in emerging applications such as SPM-based nanoscale combinatorial-science studies, image-based control for subnanometer-scale studies, and imaging of large soft biosamples with SPMs.

https://faculty.washington.edu/devasia/Research/Papers/2009_Feedforward_review_paper.pdf

A review of feedforward control approaches in nanopositioning for high-speed spm

2.4. Temperature Effects 527 2.4.1. Effect on Material Properties 528 2.4.2. Effect on Geometry 528 3. Detection Schemes 528 3.1. Optical Lever 528 3.2. Interferometer 529 3.3. Piezoresistive 529 3.4. Capacitive 529 4. Design, Materials, and Fabrication 529 4.1. Design Considerations 530 4.2. Fabrication of Silicon-based Cantilevers 530 4.2.1. Film Deposition 530 4.2.2. Photolithography 530 4.2.3. Etching 530 4.2.4. Doping 530 4.3. Fabrication of Polymeric Cantilevers 531 5. Chemical Selectivity 531 6. Chemical Applications 533 6.1. Volatile Organics 533 6.2. Chemical Warfare Agents 534 6.3. Explosives 534 6.4. Toxic Metal Ions 534 7. Biological Applications 534 7.1. Cells 534 7.2. Viruses 534 7.3. Antigen−Antibody Interactions 535 7.4. DNA Hybridization 536 7.5. Enzymes 537 8. Recommendations for Future Work 538 8.1. Guidelines for Reporting Sensor Performance 538 8.2. Experimental Design Considerations 538 8.3. Fruitful Areas for Further Research 539 8.3.1. More Selective Coatings 539 8.3.2. Increased Sensitivity and Faster Response 539

Microcantilevers: Sensing Chemical Interactions via Mechanical Motion

An atomic force microscope (AFM) design providing a focused spot of order 7 μm in diameter was used to analyze the motion of vibrating cantilevers in liquid. Picking an operating frequency for tapping mode AFM operation in liquid is complex because there is typically a large number of sharp peaks in the response spectrum of cantilever slope amplitude versus drive frequency. The response spectrum was found to be a product of the cantilever’s broad thermal noise spectrum and an underlying fluid drive spectrum containing the sharp peaks. The geometrical shape of transverse cantilever motion was qualitatively independent of the fluid drive spectrum and could be approximately reproduced by a simple theoretical model. The measurements performed give new insights into the behavior of cantilevers during tapping mode AFM operation in liquid.

http://www.bioforce.uni-tuebingen.de/pubs/Schaffer_1996_JAP.pdf

Studies of vibrating atomic force microscope cantilevers in liquid

Development of a scanning laser microscope for magneto-optic studies of thin magnetic films

The deflection control of a small cantilever is described, which operates using a single active piezoelectric element and optical vibration sensing, so that unwanted vibrations in the cantilever are removed, and yet it remains possible to deflect the cantilever statically or dynamically as required. Such a control system is directly applicable to the very small cantilevers found in scanning probe microscopes, such as atomic force and magnetic force microscopes, the resolution of which is limited by unwanted vibration.

Active vibration control and actuation of a small cantilever for applications in scanning probe instruments

Three-dimensional (3-D) finite element models have been utilized to simulate electromagnetic behaviors in spin-tunneling random access memory (STram). The most significant contributors have been identified. Compared with conventional current-in-plane (CIP) giant magneto-resistive (GMR) memory, whose signal level is inversely proportional to the square root of the storage density, these current-perpendicular-to-plane (CPP) STram elements provide an excellent readout property in that their signal level is independent of their cross-section area. This result is so attractive that the density of STram should not be limited by signal degradation. Moreover, a magnetic flux closure design was found to reduce the crossfeed by about a factor of five, compared with conventional keeperless design, which is the most favored approach for achieving 10/sup 9/ bits/cm/sup 2/ areal density. Although the storage mechanism described in this paper is made of STram, the flux-closure design could be generally applicable to other magnetic solid state memories.

Feasibility of ultra-dense spin-tunneling random access memory

A homodyne polarization laser interferometer is presented for high-speed measurement of small displacements. No modulation technique is used, so the opto-mechanical setup is relatively simple. The dual-beam arrangement enables the displacement to be measured while the use of polarization interferometry enables the determination of the directional nature of the displacement. Another feature of this interferometer lies in the fact that it is also suitable for the measurement of head-media spacing of a hard disk drive. Combined with the electronics used at present, sub-nanometer resolution is achievable. Its measurement bandwidth is limited only by the sampling rate of the A/D board being used.

Polarization interferometer for measuring small displacement

There is currently considerable interest in the development of piezoelectric materials with properties that cannot at present be attained with single-phase materials. Composite piezoelectric thick films have been prepared and characterized. These films, deposited directly onto metallized glass cantilevers, have been shown to be effective as micro-actuators.

Warwick W. Clegg

Papers

Development of a scanning laser microscope for magneto-optic studies of thin magnetic films

Active vibration control and actuation of a small cantilever for applications in scanning probe instruments

Feasibility of ultra-dense spin-tunneling random access memory

Polarization interferometer for measuring small displacement

The preparation of piezoceramic–polymer thick films and their application as micromechanical actuators