Bimodal atomic force microscopy driving the higher eigenmode in frequency-modulation mode: Implementation, advantages, disadvantages and comparison to the open-loop case

• Daniel Ebeling and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2013, 4, 198–207, doi:10.3762/bjnano.4.20

• of damping, which can be more significant when characterizing highly dissipative samples, the natural frequency is a well-defined condition, which allows the relatively easy implementation of amplitude control. That is, one can control the response amplitude by adjusting the drive amplitude, using a

• the dimensionless time, k is the cantilever force constant (stiffness) and Fts is the tip–sample interaction force. We have also used the approximation A ≈ A0 = F0Q/k [22], where F0 is the amplitude of the inertial excitation force, and have grouped the damping and excitation terms together in

Hydrogen-plasma-induced magnetocrystalline anisotropy ordering in self-assembled magnetic nanoparticle monolayers

• Alexander Weddemann,
• Judith Meyer,
• Anna Regtmeier,
• Irina Janzen,
• Dieter Akemeier and
• Andreas Hütten

Beilstein J. Nanotechnol. 2013, 4, 164–172, doi:10.3762/bjnano.4.16

• . A solution is obtained by consideration of its time-dependent extension [25] with γ the gyromagnetic ratio and α a dimensionless damping constant. The microscopic relaxation occurs on time scales significantly shorter than the time scales on which external fields change. Therefore, the microscopic

• dynamics are not in the scope of this work and the value of the damping parameter may be adjusted to provide a high numerical convergence rate. We chose α = 1 [26]. For the integration with respect to time, a backward differential formula of fifth order is applied. As a model system, we consider a two

Towards 4-dimensional atomic force spectroscopy using the spectral inversion method

• Jeffrey C. Williams and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2013, 4, 87–93, doi:10.3762/bjnano.4.10

• phenomena take place when imaging samples in high-damping (liquid) environments [18] or in multifrequency AFM characterization [19]. Illustration of the surface depression by the tip–sample impact, and successive recovery within the standard linear solid model. Z1 is the undisturbed surface position, before

Plasmonic oligomers in cylindrical vector light beams

• Mario Hentschel,
• Jens Dorfmüller,
• Harald Giessen,
• Sebastian Jäger,
• Andreas M. Kern,
• Kai Braun,
• Dai Zhang and
• Alfred J. Meixner

Beilstein J. Nanotechnol. 2013, 4, 57–65, doi:10.3762/bjnano.4.6

• are in-phase (see field distributions at spectral positions 1 and 3), exhibiting significant mode broadening due to radiative damping. It is worth mentioning that the peak position of the super-radiant mode cannot be exactly determined from the spectrum due to the presence of the resonance dip

Interpreting motion and force for narrow-band intermodulation atomic force microscopy

• Daniel Platz,
• Daniel Forchheimer,
• Erik A. Tholén and
• David B. Haviland

Beilstein J. Nanotechnol. 2013, 4, 45–56, doi:10.3762/bjnano.4.5

• additional exponential damping, which is defined as where H = 2.96 · 10−7 J is the Hamaker constant, R = 10 nm is the tip radius, γ = 2.2 · 10−7 Ns/m is the damping constant, zγ = 1.5 nm is the damping decay length and E* = 2.0 GPa is the effective stiffness. For the numerical integration of Equation 39 we

• and A as seen in the two-dimensional color maps shown in Figure 6 for the vdW-DMT force with exponential damping used in the previous section. In order to emphasize the interaction region near the point of contact, data in the h–A plane with FI < −8 nN are masked with white. In both frequency

• cantilever dynamics due to a relatively long interaction time, or a change in the hydrodynamic damping forces due to the surrounding air close to the sample surface. One should also note that at this piezo extension the minimum oscillation amplitude begins to increase again. A possible artifact of the

Thermal noise limit for ultra-high vacuum noncontact atomic force microscopy

• Jannis Lübbe,
• Matthias Temmen,
• Sebastian Rode,
• Philipp Rahe,
• Angelika Kühnle and
• Michael Reichling

Beilstein J. Nanotechnol. 2013, 4, 32–44, doi:10.3762/bjnano.4.4

• suspension and eddy-current damping systems. As an additional precaution, connections between the electronics and piezos are removed during noise measurements to ensure that measurements are not affected by any spurious electrical signals exciting the cantilever. All systems investigated here are based on

Effect of spherical Au nanoparticles on nanofriction and wear reduction in dry and liquid environments

• Dave Maharaj and
• Bharat Bhushan

Beilstein J. Nanotechnol. 2012, 3, 759–772, doi:10.3762/bjnano.3.85

• drag. In experiments where electrostatic micromotors are operated in a liquid environment, there have been problems of excessive drag and damping, which limited operating speeds, due to the use of high viscosity (20–60 cSt) oils [24]. However, studies have also demonstrated that friction and wear can

Large-scale analysis of high-speed atomic force microscopy data sets using adaptive image processing

• Blake W. Erickson,
• Séverine Coquoz,
• Jonathan D. Adams,
• Daniel J. Burns and
• Georg E. Fantner

Beilstein J. Nanotechnol. 2012, 3, 747–758, doi:10.3762/bjnano.3.84

• through either input shaping [38][39][40][41] of the drive signals or through electrical damping of the resonances [42]. For our experiments, we use a self optimizing method that determines the scanner resonances and compensates them with an input shaper [38]. Using this resonance-compensator system, the

Mapping mechanical properties of organic thin films by force-modulation microscopy in aqueous media

• Jianming Zhang,
• Zehra Parlak,
• Carleen M. Bowers,
• Terrence Oas and
• Stefan Zauscher

Beilstein J. Nanotechnol. 2012, 3, 464–474, doi:10.3762/bjnano.3.53

• forces, they often do not allow direct interpretation of the data in terms of the surface mechanical properties, due to cantilever damping in solution and the complex forces that the probe experiences when jumping in and out of contact with the surface. Alternatively, dynamic variations of contact mode

• microscopy (AFAM) [31], and contact resonance AFM (CR-AFM) [32][33][34][35], contact resonance frequencies are deliberately chosen to enhance the imaging sensitivity. However, acoustic AFM imaging in solution is challenging since the liquid phase complicates the cantilever dynamics through fluid damping. To

• substrates is further complicated by viscous damping effects [49], particularly when imaging in an aqueous environment. To better interpret image contrast in that case, one needs to understand the dependence of amplitude and phase on surface stiffness, and one needs a method to select the proper contact

Repulsive bimodal atomic force microscopy on polymers

• Alexander M. Gigler,
• Christian Dietz,
• Maximilian Baumann,
• Nicolás F. Martinez,
• Ricardo García and
• Robert W. Stark

Beilstein J. Nanotechnol. 2012, 3, 456–463, doi:10.3762/bjnano.3.52

• interaction between the tip and the sample is short (typically less than 10% of a cycle) and has a sharply peaked repulsive force and adhesion caused by a water meniscus [24]. The interaction peak for polystyrene is broader, and energy loss is caused by viscous damping [25]. Comparing the bimodal APD curves

• of the second eigenmode is smaller (4.5 nm) than for PB (4.7 nm). The average damping compared to the free amplitude is 90% and 95% for the PS and PB parts of the SB sample, respectively. This means that the PB part is more compliant and more dissipative than the PS part, which has already been

Wavelet cross-correlation and phase analysis of a free cantilever subjected to band excitation

• Francesco Banfi and
• Gabriele Ferrini

Beilstein J. Nanotechnol. 2012, 3, 294–300, doi:10.3762/bjnano.3.33

• due to a less abrupt damping of the oscillaton motion. Since the oscillator signal extending beyond the driver pulse can carry useful information but is not visible in the cross correlation, an artificial signal can be used as a reference. The phase of the oscillator can be tracked by correlating it

Simultaneous current, force and dissipation measurements on the Si(111) 7×7 surface with an optimized qPlus AFM/STM technique

• Zsolt Majzik,
• Martin Setvín,
• Andreas Bettac,
• Albrecht Feltz,
• Vladimír Cháb and
• Pavel Jelínek

Beilstein J. Nanotechnol. 2012, 3, 249–259, doi:10.3762/bjnano.3.28

• “apparent dissipation”. Recently Labuda et al. [55] showed that the apparent damping can be attributed to the transfer function of the piezo-acoustic excitation system. Therefore the dissipation signal needs to be carefully analyzed because it is one of the best indicators of the instrumental artifacts. As

• damping measured above the corner hole as well. The dissipation signal becomes flat after the correction at large distances. A minor increase of the dissipation signal appears upon the onset of the chemical force above the adatom site. Therefore, we can attribute the origin of the dissipation signal to

• tunneling current does not induce artificial damping up to 100 nA at room temperature. The dissipation detected by the amplitude regulator is the result of mainly two contributions. The first one, which has a long-range characteristic, is related to the instrumentation and can be subtracted. The second one

A measurement of the hysteresis loop in force-spectroscopy curves using a tuning-fork atomic force microscope

• Manfred Lange,
• Dennis van Vörden and
• Rolf Möller

Beilstein J. Nanotechnol. 2012, 3, 207–212, doi:10.3762/bjnano.3.23

• –distance curves upon approach and retraction. Furthermore, a second dissipation process was identified through the damping of the oscillation while the molecule on the tip is in contact with the surface. This dissipation process occurs mainly during the retraction of the tip. It reaches a maximum value of

• constant by a second control loop. The amplitude control loop provides valuable information on nonconservative interactions between the tip apex and the sample, which cause damping of the oscillation amplitude [3]. The excitation energy needed to keep the oscillation amplitude constant is directly related

• current was found. By comparison to other measurements this may be attributed to the molecule between the tip and the surface. A second dissipation process is observed through the damping of the oscillation of the tip. It occurs in every cycle of the oscillation, hence many thousands of times during the

Theoretical study of the frequency shift in bimodal FM-AFM by fractional calculus

• Elena T. Herruzo and
• Ricardo Garcia

Beilstein J. Nanotechnol. 2012, 3, 198–206, doi:10.3762/bjnano.3.22

• modeling the behavior of polymers and in viscoelastic-damping models. In general, there is a near-continuous transformation of a function into its derivative by means of fractional derivatives. To illustrate this, Figure 2 shows the behavior of a function, together with its derivative, half-derivative and

Quantitative multichannel NC-AFM data analysis of graphene growth on SiC(0001)

• Christian Held,
• Thomas Seyller and
• Roland Bennewitz

Beilstein J. Nanotechnol. 2012, 3, 179–185, doi:10.3762/bjnano.3.19

• to several complementary signals, such as topography, damping, and contact potential. The traditional presentation of such data sets in adjacent figures or in colour-coded pseudo-three-dimensional plots gives only a qualitative impression. We introduce two-dimensional histograms for the

qPlus magnetic force microscopy in frequency-modulation mode with millihertz resolution

• Maximilian Schneiderbauer,
• Daniel Wastl and
• Franz J. Giessibl

Beilstein J. Nanotechnol. 2012, 3, 174–178, doi:10.3762/bjnano.3.18

• sensitive to force gradients down to ≈ 5 × 10−7 Nm−1. All experiments presented here were performed under ambient conditions. For vibration isolation the microscope is mounted on a mechanical double damping stage [16]. We used the Nanonis SPM [17] control electronics and the Multipass configuration to

Current-induced forces in mesoscopic systems: A scattering-matrix approach

• Niels Bode,
• Silvia Viola Kusminskiy,
• Reinhold Egger and
• Felix von Oppen

Beilstein J. Nanotechnol. 2012, 3, 144–162, doi:10.3762/bjnano.3.15

• freedom. These forces control the Langevin dynamics of the mechanical modes. Specifically, we derive expressions for the (typically nonconservative) mean force, for the (possibly negative) damping force, an effective “Lorentz” force that exists even for time-reversal-invariant systems, and the fluctuating

• situations, the current-induced forces have been also studied within a scattering matrix approach in the context of quantum measurement back-action [32] (see also [33]), momentum-transfer statistics [34], and of magnetic systems to describe Gilbert damping [35]. Current-induced forces have been shown to be

• expression which is evidently positive. Damping matrix: So far, we were able to express quantities in terms of the frozen S-matrix only. This is no longer the case for the first correction to the strictly adiabatic approximation, given by Equation 27 and Equation 28. We start here with the first of these

Mechanical characterization of carbon nanomembranes from self-assembled monolayers

• Xianghui Zhang,
• André Beyer and
• Armin Gölzhäuser

Beilstein J. Nanotechnol. 2011, 2, 826–833, doi:10.3762/bjnano.2.92

• damping capacity is thus calculated based on the ratio of energy dissipated to energy stored, and the corresponding values are ~3.1%, ~9.8% and ~17.6%, respectively. When a CNM was loaded at a lower stress (~163 MPa), the deflection remained constant over time. However, when it was loaded at a higher

Current-induced dynamics in carbon atomic contacts

• Jing-Tao Lü,
• Tue Gunst,
• Per Hedegård and
• Mads Brandbyge

Beilstein J. Nanotechnol. 2011, 2, 814–823, doi:10.3762/bjnano.2.90

• highly anharmonic regime, where the preceding eigenanalysis breaks down. One scenario is that the motion of the system will reach a limit-cycle determined by the detailed anharmonic potential and the interaction with the current [7]. In this regime the details of the damping due to the coupling with

• bias voltage, Vb = 1 V. (b) N as a function of bias voltage, Vb, at fixed gate voltage Vg = 0.6 V. Note that it diverges at the critical point when the damping (1/Q) in Figure 4 goes to zero. (a) Definition of the system regions with different types of noise contributions. Leads (L,R) have a well

Nonconservative current-induced forces: A physical interpretation

• Tchavdar N. Todorov,
• Daniel Dundas,
• Anthony T. Paxton and
• Andrew P. Horsfield

Beilstein J. Nanotechnol. 2011, 2, 727–733, doi:10.3762/bjnano.2.79

• coupling these two directional phonon modes to electrons, we will see that the electron current pumps energy into one, while damping the other. The coupling between electrons and phonons is described by scattering theory. The unperturbed, phonon-free state of the current-carrying electrons is that of the

• selection rules, setting the electronic temperature to zero, and ignoring variations in the electronic properties over energies in the region of or eV, we get where This is our final result. Equation 30 displays precisely the picture from [12]. Mode (+) experiences a damped driven motion. The damping

Charge transfer through single molecule contacts: How reliable are rate descriptions?

• Denis Kast,
• L. Kecke and
• J. Ankerhold

Beilstein J. Nanotechnol. 2011, 2, 416–426, doi:10.3762/bjnano.2.47

• equilibrated model are reduced. In Figure 8 data are shown for a ratio m0 = 4/5, where deviations occur at larger voltages, as observed in the previous figures. Obviously, due to the damping of the phonon mode the resonant steps are smeared out with increasing γ. However, the approximate model predicts this

Single-pass Kelvin force microscopy and dC/dZ measurements in the intermittent contact: applications to polymer materials

• Sergei Magonov and
• John Alexander

Beilstein J. Nanotechnol. 2011, 2, 15–27, doi:10.3762/bjnano.2.2

• frequency, approaches a sample, the probe amplitude gradually decreases, Figure 2A. This effect is caused by a squeezed air damping and attractive probe-sample force interactions. The latter are enhanced by electrostatic force interactions between the conducting probe and the sample as its counter electrode

Defects in oxide surfaces studied by atomic force and scanning tunneling microscopy

• Thomas König,
• Georg H. Simon,
• Lars Heinke,
• Leonid Lichtenstein and
• Markus Heyde

Beilstein J. Nanotechnol. 2011, 2, 1–14, doi:10.3762/bjnano.2.1

• based on an active vibrational damping system. The background pressure in the UHV chamber is below 4 × 10−8 Pa. The microscope stage is cooled down with a liquid helium bath cryostat (Figure 2a). A so-called exchange gas canister is situated between microscope compartment and helium bath. The exchange

Tip-sample interactions on graphite studied using the wavelet transform

• Giovanna Malegori and
• Gabriele Ferrini

Beilstein J. Nanotechnol. 2010, 1, 172–181, doi:10.3762/bjnano.1.21

• of the cantilever may show a modification of the oscillation amplitude, frequency, phase or damping. The measurement of these cantilever parameters allows to gain information on the physical properties of the sample with (sub-)molecular resolution [4][5]. The dynamic behavior of a weakly interacting

• cantilever oscillates in air or in a fluid close to a solid surface, due to a confinement effect, an increased damping is manifested as a decrease of the quality factor [14]. This effect is relevant for piezotube movements on the μm scale but not on the nm scale covered by the present measurements, where the

Ultrafine metallic Fe nanoparticles: synthesis, structure and magnetism

• Olivier Margeat,
• Marc Respaud,
• Catherine Amiens,
• Pierre Lecante and
• Bruno Chaudret

Beilstein J. Nanotechnol. 2010, 1, 108–118, doi:10.3762/bjnano.1.13

• higher energies for NPs as compared to the reference. Unfortunately, the EXAFS signal is strongly damped, which prevents further analysis of the higher energy part. Notwithstanding, the results (both shape and damping) are consistent with published data on amorphous iron [31], thus exhibiting metallic