A scanning probe microscope for magnetoresistive cantilevers utilizing a nested scanner design for large-area scans

Meier, T.; Förste, Alexander; Tavassolizadeh, Ali; Rott, Karsten; Meyners, Dirk; Gröger, Roland; Reiss, Günter; Quandt, Eckhard; Schimmel, Thomas; Hölscher, Hendrik

doi:10.3762/bjnano.6.46

Cited by 5 publications

(6 citation statements)

References 65 publications

(49 reference statements)

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“…In case of fluorescence microscopy a calibration of feature fluorescence intensity against feature height from (standard) AFM is needed for each ink [28] and even if only feature area is extracted, fluorescent doping of the ink is naturally inevitable [29]. Details on the specially designed ultra-large scale area AFM scan setup as well as validation measurements on test structures using this scanner setup are described elsewhere [31].…”

Section: Afm Analysis With Ultra-large Scan Rangementioning

confidence: 99%

Ultra-large scale AFM of lipid droplet arrays: investigating the ink transfer volume in dip pen nanolithography

et al. 2015

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There are only few quantitative studies commenting on the writing process in dip-pen nanolithography with lipids. Lipids are important carrier ink molecules for the delivery of bio-functional patters in bio-nanotechnology. In order to better understand and control the writing process, more information on the transfer of lipid material from the tip to the substrate is needed. The dependence of the transferred ink volume on the dwell time of the tip on the substrate was investigated by topography measurements with an atomic force microscope (AFM) that is characterized by an ultra-large scan range of 800 × 800 μm(2). For this purpose arrays of dots of the phospholipid1,2-dioleoyl-sn-glycero-3-phosphocholine were written onto planar glass substrates and the resulting pattern was imaged by large scan area AFM. Two writing regimes were identified, characterized of either a steady decline or a constant ink volume transfer per dot feature. For the steady state ink transfer, a linear relationship between the dwell time and the dot volume was determined, which is characterized by a flow rate of about 16 femtoliters per second. A dependence of the ink transport from the length of pauses before and in between writing the structures was observed and should be taken into account during pattern design when aiming at best writing homogeneity. The ultra-large scan range of the utilized AFM allowed for a simultaneous study of the entire preparation area of almost 1 mm(2), yielding good statistic results.

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Section: Afm Analysis With Ultra-large Scan Rangementioning

confidence: 99%

Ultra-large scale AFM of lipid droplet arrays: investigating the ink transfer volume in dip pen nanolithography

et al. 2015

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“…As shown in Figure 7, this achievement extends the application of such sensors to dynamic devices e.g., dynamic mode AFM [15]. As a TMR-based AFM cantilever is oscillated at its resonance frequency (Figure 7a), upward and downward bending causes stress alternation

σ (t)

between tensile and compressive stresses.…”

Section: Resultsmentioning

confidence: 69%

“…Figure 7c shows a topography image of a PMMA grating obtained by dynamic imaging using a TMR sensor read-out [6]. Having studied TMR sensors in terms of minimum detectable deflection as height and phase contrasts, atomic-step edges of 2.54 Å on Au (111) terraces and self-assembled monolayers of peruorodecyltrichlorosilane have been successfully imaged by amplitude and frequency modulated AFM [15]. …”

Section: Resultsmentioning

confidence: 99%

“…In particular, magnetostrictive TMR sensors with CoFeB/MgO/CoFeB structures [3,5,6] offer more scalability compared to magnetostrictive giant magnetoresistance sensors [7,8,9,10] and higher gauge factors compared to AlO x -based TMR sensors with amorphous CoFeB [11], crystalline Co 50 Fe 50 [12] and amorphous (Fe 90 Co 10 ) 78 Si 12 B 10 [13] electrodes. The CoFeB/MgO/CoFeB TMR sensors have been successfully incorporated into membranes for pressure sensing [5,14] and microcantilevers for atomic force microscopy (AFM) [6,15]. …”

Section: Introductionmentioning

confidence: 99%

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Tunnel Magnetoresistance Sensors with Magnetostrictive Electrodes: Strain Sensors

Tavassolizadeh

Rott

Meier

et al. 2016

Sensors

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Magnetostrictive tunnel magnetoresistance (TMR) sensors pose a bright perspective in micro- and nano-scale strain sensing technology. The behavior of TMR sensors under mechanical stress as well as their sensitivity to the applied stress depends on the magnetization configuration of magnetic tunnel junctions (MTJ)s with respect to the stress axis. Here, we propose a configuration resulting in an inverse effect on the tunnel resistance by tensile and compressive stresses. Numerical simulations, based on a modified Stoner–Wohlfarth (SW) model, are performed in order to understand the magnetization reversal of the sense layer and to find out the optimum bias magnetic field required for high strain sensitivity. At a bias field of −3.2 kA/m under a 0.2×10-3 strain, gauge factors of 2294 and −311 are calculated under tensile and compressive stresses, respectively. Modeling results are investigated experimentally on a round junction with a diameter of 30±0.2sans-serifμm using a four-point bending apparatus. The measured field and strain loops exhibit nearly the same trends as the calculated ones. Also, the gauge factors are in the same range. The junction exhibits gauge factors of 2150±30 and −260 for tensile and compressive stresses, respectively, under a −3.2 kA/m bias magnetic field. The agreement of the experimental and modeling results approves the proposed configuration for high sensitivity and ability to detect both tensile and compressive stresses by a single TMR sensor.

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“…Importantly, our software-only alignment scheme was implemented on a commercial AFM (Cypher ES, Asylum Research). Hence, it can be immediately implemented at no cost on Asylum Research AFMs or custom-built AFMs controlled by an Asylum controller. − To promote such adoption, we have shared the source code for our algorithm and accompanying documentation via GitHub . Our algorithm is extendable to other commercial AFMs that support adequate flexibility in creating user-defined data-acquisition protocols.…”

Section: Resultsmentioning

confidence: 99%

Going Vertical To Improve the Accuracy of Atomic Force Microscopy Based Single-Molecule Force Spectroscopy

et al. 2017

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Single-molecule force spectroscopy (SMFS) is a powerful technique to characterize the energy landscape of individual proteins, the mechanical properties of nucleic acids, and the strength of receptor-ligand interactions. Atomic force microscopy (AFM)-based SMFS benefits from ongoing progress in improving the precision and stability of cantilevers and the AFM itself. Underappreciated is that the accuracy of such AFM studies remains hindered by inadvertently stretching molecules at an angle while measuring only the vertical component of the force and extension, degrading both measurements. This inaccuracy is particularly problematic in AFM studies using double-stranded DNA and RNA due to their large persistence length (p ≈ 50 nm), often limiting such studies to other SMFS platforms (e.g., custom-built optical and magnetic tweezers). Here, we developed an automated algorithm that aligns the AFM tip above the DNA's attachment point to a coverslip. Importantly, this algorithm was performed at low force (10-20 pN) and relatively fast (15-25 s), preserving the connection between the tip and the target molecule. Our data revealed large uncorrected lateral offsets for 100 and 650 nm DNA molecules [24 ± 18 nm (mean ± standard deviation) and 180 ± 110 nm, respectively]. Correcting this offset yielded a 3-fold improvement in accuracy and precision when characterizing DNA's overstretching transition. We also demonstrated high throughput by acquiring 88 geometrically corrected force-extension curves of a single individual 100 nm DNA molecule in ∼40 min and versatility by aligning polyprotein- and PEG-based protein-ligand assays. Importantly, our software-based algorithm was implemented on a commercial AFM, so it can be broadly adopted. More generally, this work illustrates how to enhance AFM-based SMFS by developing more sophisticated data-acquisition protocols.

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A scanning probe microscope for magnetoresistive cantilevers utilizing a nested scanner design for large-area scans

Cited by 5 publications

References 65 publications

Ultra-large scale AFM of lipid droplet arrays: investigating the ink transfer volume in dip pen nanolithography

Ultra-large scale AFM of lipid droplet arrays: investigating the ink transfer volume in dip pen nanolithography

Tunnel Magnetoresistance Sensors with Magnetostrictive Electrodes: Strain Sensors

Going Vertical To Improve the Accuracy of Atomic Force Microscopy Based Single-Molecule Force Spectroscopy

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