Weak magnetic field superconductor resistive sensors in comparison with semiconductor and magnetoresistive sensors

摘要

Weak magnetic field superconductor resistive sensors are fabricated and compared with various known types of the magnetoresistive and semiconductor sensors. The magnetically sensitive characteristics of the sensors are analyzed at room temperature and liquid-nitrogen temperature. Their resolution by the magnetic field delta B and by the magnetic flux 60 are unsatisfactory, namely, delta B >= 3 nT and delta phi >= 10 phi(0). Thick films of the ceramic HTS material of the composition Bi-2223 were fabricated, for which the magnetic sensitivity S similar to 44 V/T, delta B similar to 2 nT, and delta phi similar to 3 phi(0) are realized. It is shown that the value of S of the film increases significantly due to the size effect. This effect is taken into account, and the expected characteristics are presented, namely, S >= 1000 V/T, delta B <= 0.01 nT, delta phi <= 0.002 phi(0), and the dynamic measurement range >= 150 dB. (c) 2007 Elsevier B.V. All rights reserved.