November 5, 2026 at 1:30 PMScience › Physics1 min read

Micro-Hall sensor on GaAs/AlGaAs measures sample magnetization down to 15 mK in fields up to 30 T

Authors built a multi-cross micro-Hall sensor for dc magnetometry of small bulk samples at millikelvin temperatures and high fields, and tested it on three materials.

A multi-cross micro-Hall sensor made from an MBE-grown GaAs/AlGaAs heterostructure is described in Chinese Physics B doi.org. The device performs dc magnetization measurements at temperatures down to about 15 mK and in dc magnetic fields up to 30 T doi.org. Bulk samples from 100 μm to 1 mm in size can be measured doi.org.

According to the authors, the resolution is better than 1 μT with a 1 μA excitation at 13.77 Hz doi.org. For testing, they recorded the field-dependent magnetization plateaus of the triangular-lattice quantum magnet K2Co2(SeO3)3 at 20 mK, the antiferromagnetic transition of K3GdTe2O9 near 220 mK, and quantum oscillations in a ruthenium single crystal doi.org. The paper also provides a simple sample-mounting setup for reproducible measurements.