3D scanning Hall probe microscopy with 700 nm resolution

Oral, Ahmet
In this report, we present a three dimensional (3D) imaging of magnetic field vector (B) over right arrow (x,y,z) emanating from the magnetic material surfaces using a scanning Hall probe microscopy (3D-SHPM) down to a 700 nm spatial resolution. The Hall probe is used to measure B-z(x,y) on the specimen surface at different heights with the step size of Delta z = 250 nm, as we move away from the surface in z direction, until the field decays to zero. These set of images are then used to get partial derivative B-z(x,y)/partial derivative x and partial derivative B-z(x,y)/partial derivative y at different z by numerical differentiation. Using the Maxwell's equations in the source free region, B-x(x,y) and B-y(x,y) can be calculated by integrating partial derivative B-z(x,y)/partial derivative x and partial derivative B-z(x,y)/partial derivative y in the z direction. Alternatively, the gradients can also be measured in the Hall gradiometer configuration directly. The operation of the 3D-SHPM is demonstrated by imaging B-x(x,y), B-y(x,y) and B-z(x,y) on a hard disk specimen at a 700 nm resolution, using both of these methods at 77 K. The system is capable of operating from 300 K down to 4 K range. Published by AIP Publishing.


Electrical impedance tomography using the magnetic field generated by injected currents
Birgul, O; Ider, YZ (1996-11-03)
In 2D EIT imaging, the internal distribution of the injected currents generate a magnetic field in the imaging region which can be measured by magnetic resonance imaging techniques. This magnetic field is perpendicular to the imaging region on the imaging region and it can be used in reconstructing the conductivity distribution inside the imaging region. For this purpose, internal current distribution is found using the finite element method. The magnetic fields due to this current is found using Biot-Savar...
Scanning Hall Probe Microscopy (SHPM) using quartz crystal AFM feedback
Dede, M.; Uerkmen, K.; Girisen, Oe.; Atabak, M.; Oral, Ahmet; Farrer, I.; Ritchie, D. (American Scientific Publishers, 2008-02-01)
Scanning Hall Probe Microscopy (SHPM) is a quantitative and non-invasive technique for imaging localized surface magnetic field fluctuations such as ferromagnetic domains with high spatial and magnetic field resolution of similar to 50 nm and 7 mG/Hz(1/2) at room temperature. In the SHPM technique, scanning tunneling microscope (STM) or atomic force microscope (AFM) feedback is used to keep the Hall sensor in close proximity of the sample surface. However, STM tracking SHPM requires conductive samples; ther...
Nano and micro Hall-effect sensors for room-temperature scanning hall probe microscopy
SANDHU, A; OKAMOTO, A; SHİBASAKİ, I; Oral, Ahmet (2004-06-01)
GaAs/AlGaAs two-dimensional electron gas (GaAs-2DEG) Hall probes are impractical for sub-micron room-temperature scanning Hall microscopy (RT-SHPM), due to surface depletion effects that limit the Hall driving current and magnetic sensitivity (B in). Nano and micro Hall-effect sensors were fabricated using Bi and InSb thin films and shown to be practical alternatives to GaAs-2DEG probes for high resolution RT-SHPM. The GaAs-2DEG and InSb probes were fabricated using photolithography and the Bi probes by opt...
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...
Spatial modulation of THz beams for imaging applications
Altan, Hakan (null; 2015-10-16)
Techniques based on compressive sensing allow us to image fields at faster rates and at our labs in METU we have been experimenting with imaging based on spatial modulation of THz beams using single pixel detectors [1]. However these studies are based on discrete patterns using metal sheets. These techniques would benefit greatly if we could modulate the THz field. For example, optical modulators play a key role in optoelectronics and communication systems. Electro-optic, acousto-optic and thermo-optic effe...
Citation Formats
M. DEDE, R. AKRAM, and A. Oral, “3D scanning Hall probe microscopy with 700 nm resolution,” APPLIED PHYSICS LETTERS, pp. 0–0, 2016, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/34513.