Chinese magnetic sensor breakthrough may help smartwatch detect submarine 500 metres deep

Chinese scientists have achieved a significant breakthrough in magnetic sensor technology, developing a Hall-effect sensor so sensitive it could theoretically detect a submarine from 500 meters below the surface. This advancement, achieved by a team from the Hefei Institutes of Physical Science and the Ningbo Institute of Materials Technology and Engineering, could pave the way for everyday devices like smartwatches to detect underwater anomalies.

The newly developed sensor is remarkably small, fitting onto a chip no larger than a grain of dust. Its potential application could allow a smartwatch to alert a user to a "magnetic anomaly detected – possible submarine passing 500 metres below." This capability addresses a decades-old challenge in sensor technology: the trade-off between increasing sensitivity and managing the accompanying noise.

Hall-effect sensors are already common in many electronic devices, including smartphones, cars, and medical scanners. They function by generating a small voltage when exposed to a magnetic field, making them simple, cost-effective, and compact. However, previous attempts to enhance their sensitivity often resulted in increased noise, akin to amplifying static when turning up radio volume.

The research, published in the journal Physical Review Letters on July 17, signifies a major step in overcoming this sensitivity-versus-noise barrier. The implications extend beyond submarine detection, potentially improving a wide range of applications that rely on detecting faint magnetic fields.