Frequency modulation detection using highdkantilevers for enhanced force microscope sensitivity
01 Jan 2001-
TL;DR: In this paper, a frequency modulation (FM) technique has been demonstrated which ennances the sensitivity of attractive mode force microscopy by an order of magnitude or more, which is made possible by operating in a moderate vacuum ( < 10 ’ Torr).
Abstract: A new frequency modulation (FM) technique has been demonstrated which ennances the sensitivity of attractive mode force microscopy by an order of magnitude or more. Increased sensitivity is made possible by operating in a moderate vacuum ( < 10 ’ Torr), which increases the Q of the vibrating cantilever. In the FM technique, the cantilever serves as the frequency determining element of an oscillator. Force gradients acting on the cantilever cause instantaneous frequency modulation of the oscillator output, which is demodulated with a FM detector. Unlike conventional “slope detection,” the FM technique offers increased sensitivity through increased Q without restricting system bandwidth. Experimental comparisons of FM detection in vacuum (Q50 000) versus slope detection in air (Q100) demonstrated an improvement of more than 10 times in sensitivity for a fixed bandwidth. This improvement is evident in images of magnetic transitions on a thin-film CoPtCr magnetic disk. In the future, the increased sensitivity offered by this technique should extend the range of problems accessible by force microscopy.
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TL;DR: Titanium dioxide is the most investigated single-crystalline system in the surface science of metal oxides, and the literature on rutile (1.1) and anatase surfaces is reviewed in this paper.
7,056 citations
Book•
01 Jan 2006TL;DR: In this paper, the authors proposed a method for propagating and focusing of optical fields in a nano-optics environment using near-field optical probes and probe-sample distance control.
Abstract: 1. Introduction 2. Theoretical foundations 3. Propagation and focusing of optical fields 4. Spatial resolution and position accuracy 5. Nanoscale optical microscopy 6. Near-field optical probes 7. Probe-sample distance control 8. Light emission and optical interaction in nanoscale environments 9. Quantum emitters 10. Dipole emission near planar interfaces 11. Photonic crystals and resonators 12. Surface plasmons 13. Forces in confined fields 14. Fluctuation-induced phenomena 15. Theoretical methods in nano-optics Appendices Index.
3,772 citations
TL;DR: The atomic force microscope (AFM) is not only used to image the topography of solid surfaces at high resolution but also to measure force-versus-distance curves as discussed by the authors, which provide valuable information on local material properties such as elasticity, hardness, Hamaker constant, adhesion and surface charge densities.
3,281 citations
TL;DR: The most widely used technique for atomic-resolution force microscopy in vacuum is frequency-modulation AFM (FM-AFM), as well as other dynamic methods as discussed by the authors.
Abstract: This article reviews the progress of atomic force microscopy in ultrahigh vacuum, starting with its invention and covering most of the recent developments. Today, dynamic force microscopy allows us to image surfaces of conductors and insulators in vacuum with atomic resolution. The most widely used technique for atomic-resolution force microscopy in vacuum is frequency-modulation atomic force microscopy (FM-AFM). This technique, as well as other dynamic methods, is explained in detail in this article. In the last few years many groups have expanded the empirical knowledge and deepened our theoretical understanding of frequency-modulation atomic force microscopy. Consequently spatial resolution and ease of use have been increased dramatically. Vacuum atomic force microscopy opens up new classes of experiments, ranging from imaging of insulators with true atomic resolution to the measurement of forces between individual atoms.
1,948 citations
TL;DR: In this paper, the authors review the fundamentals, applications and future tendencies of dynamic atomic force microscopy (AFM) methods and present a detailed quantitative comparison between theoretical simulations and experiment.
1,908 citations
References
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IBM1
TL;DR: In this paper, a modified version of the atomic force microscope is introduced that enables a precise measurement of the force between a tip and a sample over a tip-sample distance range of 30-150 A.
Abstract: A modified version of the atomic force microscope is introduced that enables a precise measurement of the force between a tip and a sample over a tip‐sample distance range of 30–150 A. As an application, the force signal is used to maintain the tip‐sample spacing constant, so that profiling can be achieved with a spatial resolution of 50 A. A second scheme allows the simultaneous measurement of force and surface profile; this scheme has been used to obtain material‐dependent information from surfaces of electronic materials.
1,405 citations
TL;DR: In this article, a force microscope is used to measure the magnetic force between a magnetized tip and the scanned surface, which shows promise for the high-resolution mapping of both static and dynamic magnetic fields.
Abstract: We describe a new method for imaging magnetic fields with 1000 A resolution. The technique is based on using a force microscope to measure the magnetic force between a magnetized tip and the scanned surface. The method shows promise for the high‐resolution mapping of both static and dynamic magnetic fields.
1,113 citations
TL;DR: In this article, a high-sensitivity fiber-optic displacement sensor for atomic force microscopy is described based on the optical interference occurring in the micron-sized cavity formed between the cleaved end of a singlemode optical fiber and the microscope cantilever.
Abstract: A high‐sensitivity fiber‐optic displacement sensor for atomic force microscopy is described. The sensor is based on the optical interference occurring in the micron‐sized cavity formed between the cleaved end of a single‐mode optical fiber and the microscope cantilever. As a result of using a diode laser light source and all‐fiber construction, the sensor is compact, mechanically robust, and exhibits good low‐frequency noise behavior. Peak‐to‐peak noise in a dc to 1 kHz bandwidth is less than 0.1 A. Images are presented demonstrating atomic resolution of graphite and magnetic force imaging of bits written on a magnetic disk.
634 citations
TL;DR: In this paper, the authors used the ac detection method which senses the force gradient acting on a small magnetic tip due to fields emanating from the domain structure in the sample, and showed that the final 20 μm is essentially single domain with magnetization approximately parallel with the tip axis.
Abstract: This paper discusses the principles of magnetic force microscopy (MFM) and its application to magnetic recording studies. We use the ac detection method which senses the force gradient acting on a small magnetic tip due to fields emanating from the domain structure in the sample. Tip fabrication procedures are described for two types of magnetic tips: etched tungsten wires with a sputter‐deposited magnetic coating and etched nickel wires. The etched nickel wires are shown to have an apex radius on the order of 30 nm and a taper half‐angle of approximately 3°. Lorentz‐mode transmission electron microscopy of the nickel tips reveals that the final 20 μm is essentially single domain with magnetization approximately parallel with the tip axis. Images of written bit transitions are presented for several types of magnetic media, including CoPtCr, CoSm, and CoCr thin films, as well as γ‐Fe2O3 particulate media. In general, the written magnetization patterns are seen with high contrast and with resolution better ...
606 citations
IBM1
TL;DR: A new technique, using force microscopy, for studying the mechanism of charge exchange between contacting surfaces when at least one of them is insulating with greater lateral resolution than has been previously possible.
Abstract: One of the oldest unresolved problems in physics is the mechanism of charge exchange between contacting surfaces when at least one of them is insulating. We describe a new technique, using force microscopy, for studying this problem with greater lateral resolution than has been previously possible. The force microscope is shown to have 0.2 \ensuremath{\mu}m lateral resolution and the sensitivity to detect 3 electronic charges. In contact-charging experiments between the microscope tip and polymethyl methacrylate, the charged region was much larger than the expected contact area and bipolar charge exchange was observed.
483 citations