A chemical element used as a superconductor in the fabrication of sensitive magnetic sensors.Niobium is a chemical element (symbol Nb, atomic number 41) that becomes a superconductor at temperatures below 9.2 K. In its superconducting state, it conducts electricity with zero resistance, making it invaluable for creating extremely sensitive magnetic field sensors, such as SQUIDs (Superconducting Quantum Interference Devices). These sensors can detect minuscule magnetic fields, from brain activity to subtle changes in materials.
Niobium was discovered in 1801 by Charles Hatchett, who named it columbium. Its superconducting properties were identified in the 1930s, and its use in SQUIDs began in the 1960s following Brian Josephson's theoretical prediction of the Josephson effect.
When niobium is cooled below its critical temperature, its electrons form Cooper pairs that flow without resistance. In a SQUID, a loop of niobium with one or two Josephson junctions (thin insulating barriers) exploits quantum interference to convert magnetic flux into a measurable voltage. The extreme sensitivity arises because the device responds to changes as small as a single quantum of magnetic flux.
Niobium-based SQUIDs are used in medical magnetoencephalography, geological surveying, and materials testing, as well as in quantum computing research for reading qubit states.
Niobium is also used in particle accelerators, such as the Large Hadron Collider, where its superconducting cavities accelerate protons to near light speed.

















