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

- Published: 2026-11-05 11:30 UTC
- Section: Science › Instruments & experiments
- Tags: multi-cross micro-Hall sensor, dc magnetization, millikelvin magnetometry, 30 T magnetic field, GaAs/AlGaAs heterostructure, K2Co2(SeO3)3, K3GdTe2O9, quantum oscillations ruthenium, Chinese Physics B
- URL: https://realtech.media/news/rt-c5dd69d53c0e78a5b67bd93c_micro_hall_sensor/

**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.**

![Micro-Hall sensor on GaAs/AlGaAs measures sample magnetization down to 15 mK in fields up to 30 T](https://sgzwpqqelzmajkcubgkl.supabase.co/storage/v1/object/public/rt-media/2026/11/6cc9a4758af2b76a.jpg)
*Antonín Ryska, Wikimedia Commons, CC BY 4.0*

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

According to the authors, the resolution is better than 1 μT with a 1 μA excitation at 13.77 Hz [1]. 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 [1]. The paper also provides a simple sample-mounting setup for reproducible measurements.

## Sources

1. [Chinese Physics B](https://doi.org/10.1088/1674-1056/aeba69)
2. [arXiv · препринт](https://arxiv.org/abs/2611.06676v1)

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Source: RealTech, realtech.media — https://realtech.media/news/rt-c5dd69d53c0e78a5b67bd93c_micro_hall_sensor/