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

• provides information and guidelines that can be useful in selecting the most appropriate operation mode to characterize different samples in the most efficient and reliable way. Keywords: amplitude-modulation; atomic force microscopy; frequency-modulation; phase-locked loop; spectroscopy; Introduction

• scheme of the AM-FM mode Figure 1 shows a diagram of the experimental setup used, which consists of a commercial AFM system (MFP3D with ARC2 controller, Asylum Research Corporation, Santa Barbara, CA, USA) equipped with external phase-locked loop (PLL) electronics (PLL Pro 2, RHK Technology, Troy, MI

• amplitudes and phase shifts at each eigenmode of the cantilever. In contrast, the CE version of AM-FM requires either a phase-locked-loop (PLL) or a self-excitation (phase-shift-based) loop to keep the phase locked at 90 degrees (so far we have observed that self-excitation loops are less stable in tapping

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

• commonly performed by a phase-locked loop (PLL) circuit [2]. As schematically depicted in Figure 1, the amplitude response of the PLL unit can formally be decomposed into the amplitude response Gdemod of the demodulator and the amplitude response Gfilter of an in-loop or output filter. The characteristics

Drive-amplitude-modulation atomic force microscopy: From vacuum to liquids

• Miriam Jaafar,
• David Martínez-Martín,
• Mariano Cuenca,
• John Melcher,
• Arvind Raman and
• Julio Gómez-Herrero

Beilstein J. Nanotechnol. 2012, 3, 336–344, doi:10.3762/bjnano.3.38

• the driving force as the feedback variable for topography. Additionally, a phase-locked loop can be used as a parallel feedback allowing separation of the conservative and nonconservative interactions. We describe the basis of this mode and present some examples of its performance in three different

• constant by adjusting the amplitude of the driving force. A phase-locked loop (PLL) tracks the effective resonance frequency of the cantilever as it varies as a consequence of the tip–sample interaction. In FM, the position of the scanner in the z-direction is adjusted to keep the frequency shift constant

Graphite, graphene on SiC, and graphene nanoribbons: Calculated images with a numerical FM-AFM

• Fabien Castanié,
• Laurent Nony,
• Sébastien Gauthier and
• Xavier Bouju

Beilstein J. Nanotechnol. 2012, 3, 301–311, doi:10.3762/bjnano.3.34

• dynamic behavior of the oscillator. Briefly speaking, an important element of the FM-AFM experimental apparatus is the frequency detection by demodulation performed with the aid of a phase-locked loop (PLL). This allows measurement of the frequency shift Δf from the fundamental resonance frequency of the

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

• oscillation a phase-locked-loop system supplied by Specs Zürich (Nanonis) is used. Scanning control and data acquisition are performed by the open-source software GXSM [23] combined with home-built electronics. For image processing the free software WSXM [24] is used. Sample preparation was performed as

Molecular-resolution imaging of pentacene on KCl(001)

• Julia L. Neff,
• Jan Götzen,
• Enhui Li,
• Michael Marz and
• Regina Hoffmann-Vogel

Beilstein J. Nanotechnol. 2012, 3, 186–191, doi:10.3762/bjnano.3.20

• measurements were carried out by using a phase-locked-loop frequency demodulator from Nanonis (SPECS, Zürich, Switzerland). Typical resonance frequencies f0 and spring constants k of the cantilevers were 160 kHz and 45 N/m, respectively. Samples were investigated at room temperature and afterwards at low

Distinguishing magnetic and electrostatic interactions by a Kelvin probe force microscopy–magnetic force microscopy combination

• Miriam Jaafar,
• Oscar Iglesias-Freire,
• Luis Serrano-Ramón,
• Manuel Ricardo Ibarra,
• Jose Maria de Teresa and
• Agustina Asenjo

Beilstein J. Nanotechnol. 2011, 2, 552–560, doi:10.3762/bjnano.2.59

• dynamical modes. The tip–cantilever system oscillates at a certain frequency with a given amplitude. Due to the presence of an interaction between the tip and the sample, the amplitude and the phase of the oscillation change. In our experiments we use a PLL (Phase Locked Loop) system to keep the phase