Characteristics of a highly sensitive magnetic sensor made from a thick BPSCCO film

摘要

A highly sensitive magnetic sensor, based on a thick Bi-Pb-Sr-Ca-Cu-O (BPSCCO) film has been fabricated by use of the spray technique. The BPSCCO magnetic sensor was fabricated to retain a residual resistance R_(ms) at the boiling point of liquid nitrogen. The value of R_(ms) in the transition region (DELTA)T of the sensor, was highly sensitive to the excitation magnetic field B_(ex). Here, (DELTA)T is the region between the transitional temperature T_c~(onset) and residual resistance temperature T_c~(res). The magnetic sensitivity S of the magnetic sensor was determined as about 27 percent/(10~(-4) T) over the magnetic range from 0 T to +-10 X 10~(-4) T. That is, the value of S is about the 27 times greater than that of a giant magneto-resistance (GMR) sensor. Also exhibited were the linear characteristics of the dependence of S on B_(ex) with no hysteresis characteristics displayed. It was found that the values of S increased as the value of the resistivity sigma of the sensor decreased. The values of sigma, furthermore, increased as the values of current density J_(ms) of sensor increased. In the present paper, the ability to control the value of S for the BPSCCO magnetic sensor by the value of J_(ms) was also demonstrated.