SQUID-devices as a tool for measurement of ultraweak signals of the nanosystems

Yu.K.еvdokimov, E.S.Denisov

Russia

 

Superconducting Quantum Interference Devices (SQUID) are the most sensitive sensors of a magnetic field. Besides their use in scientific research in laboratories, they have rich potential for practical use in such areas as geophysics, biomagnetism, nondestructive testing of materials, and measurement of ultraweak signals and nanonoise. There are numerous applications (problems) where extremely weak magnetic signals should be detected and precisely amplified. Wide development of techniques of superconducting materials, and also discovery of high-temperature superconductors led to appearance and creation of preconditions to a wide distribution of the SQUID-systems intended for measurement of weak signals. Measurement of nonmagnetic weak electrical amounts and signals, such as the current, voltage, resistance, inductance, capacity, etc. is carried out by transformation of the specified amounts to a magnetic field. In this paper the comparative analysis of sensitivity of SQUID-devices and devices of amplification of weak signals on the basis of traditional semi-conductor elements is shown. The principle of operation of SQUID-devices, such as DC-SQUID and RF-SQUID is considered also, the review and the analysis of modern devices and equipment on the basis of SQUID is made.