Creating the holy grail of magnetic imaging.

• Position: Superconductivity

Scientists have taken a quantum leap toward understanding the phenomenon known as superconductivity, as researchers at the Weizmann Institute, Rehovot, Israel, have created the world's smallest SQUID--a device used to measure magnetic fields --which displays unprecedented sensitivity and resolution.

Superconductivity is a quantum phenomenon that occurs when certain materials are cooled to extremely low temperatures. Then they lose all resistance to the flow of electricity and expel the magnetic fields within them. Although used in everything from magnetic resonance imaging (MRI) scanners to particle accelerators, scientists still do not fully understand the physics that underlies the behavior of superconductors. Among other things, superconducting materials are found in the very SQUIDs used to measure superconducting properties: SQUID stands for superconducting quantum interference device.

Nano-SQUIDs are placed on probes to scan and measure the magnetic field at different points on a sample, forming an image of the entire surface--a bit like creating a heat map of a hand by measuring its temperature at individual points on the fingers and palms.

Even very sensitive SQUIDS present geometric challenges when it comes to scanning materials: they need to be as small as possible to attain the highest image resolution, and they need to get as close as possible to the sample to image the tiniest magnetic features.

Postdoctoral fellows Yonathan Anahory and Denis Vasyukov, and Ph.D. student Lior Embon, along...