3D scanning Hall probe microscopy with 700  nm resolution

In this report, we present athree dimensional(3D) imaging ofmagnetic field vectorB→(x,y,z) emanating from the magnetic material surfaces using a scanning Hall probemicroscopy(3D-SHPM) down to a 700  nmspatial resolution. The Hall probe is used tomeasureBz(x,y) on the specimen surface at different heights with the step size of Δz  = 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∂Bz(x,y)/∂x and∂Bz(x,y)/∂y at differentz by numerical differentiation. Using theMaxwell's equations in the source free region,Bx(x,y) andBy(x,y) can be calculated by integrating∂Bz(x,y)/∂x and∂Bz(x,y)/∂y in thez direction. Alternatively, the gradients can also bemeasured in the Hallgradiometer configuration directly. The operation of the3D-SHPM is demonstrated by imagingBx(x,y),By(x,y) andBz(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.

Source: Applied Physics Letters - November 4, 2016 Category: Physics Authors: M. Dede, R. Akram and A. Oral Source Type: research