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

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 δB and by the magnetic flux δφ are unsatisfactory, namely, δB ≥ 3 nT and δφ ≥ 10φ0. Thick films of the ceramic HTS material of the composition Bi-2223 were fabricated, for which the magnetic sensitivity S ∼ 44 V/T, δB ∼ 2 nT, and δφ ∼ 3φ0 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, δB ≤ 0.01 nT, δφ ≤ 0.002φ0, and the dynamic measurement range ≥150 dB