Nano-Thermometers for Temperature Imaging

National Institute of Standards and Technology, Gaithersburg, MD

Thermal MagIC will use nanometer-sized objects whose magnetic signals change with temperature. The objects would be incorporated into the liquids or solids being studied. A remote sensing system would then pick up these magnetic signals, meaning the system being studied would be free from wires. (Image: NIST)

Researchers are designing and building a fleet of tiny, ultra-sensitive thermometers that could make real-time measurements of temperature on the microscopic scale in an opaque 3D volume — which could include medical implants, refrigerators, and even the human body.

Thermal Magnetic Imaging and Control (Thermal MagIC) could revolutionize temperature measurements in many fields: biology, medicine, chemical synthesis, refrigeration, the automotive industry, plastic production, or anywhere temperature plays a critical role. Thermal MagIC will work by using nanometer-sized objects whose magnetic signals change with temperature. The objects would be incorporated into the liquids or solids being studied — the melted plastic that might be used as part of an artificial joint replacement or liquid coolant being recirculated through a refrigerator. A remote sensing system would then pick up these magnetic signals, meaning the system being studied would be free from wires or other bulky external objects.

The final product could make temperature measurements that are 10 times more precise than state-of-the-art techniques, acquired in one-tenth the time in a volume 10,000 times smaller. This equates to measurements accurate to within 25 millikelvin (thousandths of a kelvin) in as little as a tenth of a second, in a volume just a hundred micrometers (millionths of a meter) on a side.

The system aims to measure temperatures over the range from 200 to 400 kelvin (K), which is equivalent to about -99 to 260 °F. There is potential for a much larger temperature range, stretching from 4 K-600 K, that would encompass everything from supercooled superconductors to molten lead.

The first step in making the system is creating nano-sized magnets that will give off strong magnetic signals in response to temperature changes. To keep particle concentrations as low as possible, the magnets will need to be 10 times more sensitive to temperature changes than any objects that currently exist. To get that kind of signal, researchers will likely need to use multiple magnetic materials in each nano-object. A core of one substance will be surrounded by other materials like the layers of an onion.

For more information, contact Solomon Woods at This email address is being protected from spambots. You need JavaScript enabled to view it.; 301-975-2382.