Study on the use of a bismuth micro-Hall probe for magnetic imaging of ferromagnetic domain structures by room temperature scanning Hall probe microscopy

A. Sandhu, H. Masuda¹, A. Oral², S. J. Bending ³, A.Yamada⁴, and M. Konagai⁴

Dept. of Electrical and Electronic Engineering, Tokai University, Japan.
1) Toei Kogyo Ltd., Machida, Japan.
2) Dept. of Physics, Bilkent University, Turkey.
3) Dept. of Physics, University of Bath, UK.
4) Dept. of Physical Electronics, Tokyo Institute of Technology, Tokyo.

We have previously reported on the development of a new room temperature scanning Hall probe microscope system (RT-SHPM) incorporating a GaAs/AlGaAs micro-Hall probe for magnetic imaging of microscopic domains of ferromagnetic materials [1]. This time, we will describe the successful use of a bismuth (Bi) micro-Hall probe sensor with the RT-SHPM for imaging garnets and permanent magnets. At a driving current of 800 µA, the Hall coefficient, magnetic field sensitivity and spatial resolution of the Bi probe was 3.3x10-4 W/G, 0.38G/ˆHz and ~2.8µm, respectively. The room temperature magnetic field sensitivity of the Bi micro-Hall probe was comparable to that of a semiconducting 1.2 µm GaAs/AlGaAs heterostructure micro-Hall probes, which exhibited a value of 0.41G/ˆHz at a maximum driving current of 2µA. The use of Bi overcomes surface depletion effects that limit the ultimate spatial resolution of semiconducting Hall probe sensors.
[1] A. Sandhu, et.al: ICF-8, Sept. 18-21, Kyoto, 2000.