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 iop.org
Chinese Physics Biop.orgOpen source ↗. The device performs dc magnetization measurements at temperatures down to about 15 mK and in dc magnetic fields up to 30 T. Bulk samples from 100 μm to 1 mm in size can be measured.
According to the authors, the resolution is better than 1 μT with a 1 μA excitation at 13.77 Hz. 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. The paper also provides a simple sample-mounting setup for reproducible measurements.
