Chinese magnetic sensor breakthrough may help smartwatch detect submarine 500 metres deep
Picture a fisherman hauling in his nets on a calm morning at sea, when his smartwatch suddenly vibrates with an alert: “Magnetic anomaly detected – possible submarine passing 500 metres below.” Far‑fetched as it sounds, Chinese scientists have just taken a decisive step towards making that scenario real. A team from the Hefei Institutes of Physical Science and the Ningbo Institute of Materials…
Chinese researchers have created a Hall-effect magnetic sensor capable of detecting a submarine submerged up to 500 metres below the surface, according to a recent study published in Physical Review Letters. The sensor, developed by a team from the Hefei Institutes of Physical Science and the Ningbo Institute of Materials Technology and Engineering under the Chinese Academy of Sciences, is so sensitive it can detect the faint magnetic shadow of a steel-hulled submarine within a chip the size of a grain of dust.
Hall-effect sensors are commonly used in devices such as smartwatches, smartphones, car wheel-speed detectors, and hospital scanners. They work by generating a tiny voltage when a magnetic field is present, making them simple, cheap, fast, and compact. However, making them more sensitive often results in increased noise, which is a significant challenge in sensor technology.
The Chinese team discovered that the noise level in magnetic materials is directly related to the speed of spin texture movement. Slower movement leads to more noise, while faster movement reduces noise. By designing an artificial ferromagnetic structure with exceptionally rapid spin texture dynamics, the researchers maximized the material's sensitivity to magnetic fields.
The resulting sensor has an effective detection area of just 20 by 20 micrometres, making it significantly cheaper and simpler than existing alternatives. While the technology shows promise for submarine detection, practical deployment would still face numerous challenges. The current sensor sensitivity is sufficient for detecting a submarine at close range, but it falls short for long-range detection.
However, the technology holds more immediate promise in biomedical and industrial applications. The human heartbeat and brain neural activity generate magnetic signals within the sensor's operating window, making it a potential tool for brain science research and early diagnosis of heart conditions. The sensor's compact size could also be beneficial for scanning probe microscopy in imaging the microscopic structure of materials and electronics manufacturing.
Written by urgent.news from Reuters Business via SCMP's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
