Real-time scanning hall probe microscopy

Oral, Ahmet
We describe a low-noise scanning Hall probe microscope having unprecedented magnetic field sensitivity (similar to 2.9x10(-8) T/root Hz at 77 K), high spatial resolution, (similar to 0.85 mu m),nd operating in real-time (similar to 1 frame/s) for studying flux profiles at surfaces. A submicron Hall probe manufactured in a GaAs/A1GaAs two-dimensional electron gas (2DEG) is scanned over the sample to measure the surface magnetic fields using conventional scanning tunneling microscopy positioning techniques. Flux penetration into a high T-c YBa2Cu3O7-delta thin film has been observed in real time at 85 K with single vortex resolution. Flux is seen to enter the film in the form of vortex bundles as well as single flux quanta, Phi(0). (C) 1996 American Institute of Physics.


Quantitative atom-resolved force gradient imaging using noncontact atomic force microscopy
Oral, Ahmet; ÖZER, HAKAN ÖZGÜR; HOFFMANN, PM; PETHICA, JB (2001-09-17)
Quantitative force gradient images are obtained using a sub-angstrom amplitude, off-resonance lever oscillation method during scanning tunneling microscopy imaging. We report the direct observation of short-range bonds, and the measured short-range force interaction agrees well in magnitude and length scale with theoretical predictions for single bonds. Atomic resolution is shown to be associated with the presence of a prominent short-range contribution to the total force interaction. It is shown that the b...
Microscopic measurement of penetration depth in YBa2Cu3O7-delta thin films by scanning Hall probe microscopy
Oral, Ahmet; HUMPHREYS, RG; HENİNİ, M (1997-01-01)
We have used a low noise scanning Hall probe microscope to measure the penetration depth microscopically in a YBa2Cu3O7-delta thin film as a function of temperature. The instrument has high magnetic field (approximate to 2.9 x 10(-8) T HZ(-1/2) at 77 K) and spatial resolution ( approximate to 0.85 mu m). Magnetic field profiles of single vortices in the superconducting film have been successfully measured and the microscopic penetration depth of the superconductor has been extracted. We find surprisingly la...
Effect of synthesis parameters on the surface morphology of conducting polypyrrole films
Kaynak, A (1997-03-01)
Surface morphology of polypyrrole films was investigated by using atomic force and scanning electron microscopy techniques. Synthesis parameters such as dopant concentration and synthesis time and subsequent heat treatment were found to affect the surface morphology of electrochemically synthesized polypyrrole films. Mean height, root-mean-square roughness, and nodule diameter increased with increasing dopant concentration and synthesis time. Lightly doped, semiconducting films had smoother surface morpholo...
Quantitative electrostatic force measurement in AFM
JEFFERY, Steve; Oral, Ahmet; Pethica, John B. (2000-04-02)
We describe a method for measuring forces in the atomic force microscope (AFM), in which a small amplitude oscillation(similar to 1 Angstrom(p-p)) is applied to a stiff(similar to 40 N/m) cantilever below its first resonant frequency, and the force gradient is measured directly as a function of separation. We have used this instrument to measure electrostatic forces by applying an ac voltage between the tip and the sample, and observed a variation in contact potential difference with separation. We also sho...
Time-resolved microscopy of femtosecond laser filaments in fused quartz
Kadan, Viktor; Blonskyi, Ivan; Pavlov, Ihor (2022-02-01)
Detailed picture of continuous shape evolution of femtosecond laser pulse has been recorded directly in the process of filament formation in fused silica using time-resolved polarization microscopy with similar to 70 fs temporal resolution. The main stages of the pulse transformation (temporal self-compression and splitting, formation of conical wave) have been studied. The maximum temporal compression has been found to be achieved by the leading subpulse after the time splitting event. It was found that th...
Citation Formats
A. Oral and M. HENİNİ, “Real-time scanning hall probe microscopy,” APPLIED PHYSICS LETTERS, pp. 1324–1326, 1996, Accessed: 00, 2020. [Online]. Available: