RESEARCHERS at IBM are now close to making detectors based on high-temperature superconductors for measuring minute magnetic fields. These devices, known as Squids (Superconducting Quantum Interference Devices), can measure magnetic fields as small as one-billionth that of the Earth. Scientists can use them to design magnetometers sensitive enough to measure the magnetic field given off by the brain and heart.
Hospitals already use such devices to diagnose brain and heart problems, but their current machines use low-temperature superconductors operating at just over 4 kelvin. These devices are kept cool by liquid helium, and the machines are relatively bulky because of the insulation required to keep the devices cool.
Roger Koch of IBM's research centre in Yorktown Heights, New York, announced the development of a Squid made from a high temperature superconductor which works at 77 kelvin. This means the device could be kept cool with liquid nitrogen, and would need ...
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