Magnetic characteristics of bulk BPSCCO magnetic sensors fabricated by the shock compaction method: relationship between the magnetic sensitivity and thickness of the magnetic sensor

As one of the basic areas of research for the development of a highly sensitive magnetic sensor, the present authors have fabricated bulk Bi-Pb-Sr-Ca-Cu-O magnetic sensors by use of the shock compaction method, as a new fabrication technique for high-critical temperature superconductors. Values of the thickness t of the sensors, under a shock compaction pressure P of 4 GPa, are systematically changed between 0.3 and 1.1 mm to investigate the magnetic sensitivity S of the sensors. It was found that the value of S increases as the value of t decreases. The value of S for a magnetic sensor (1.1 mm in width, 8.7 mm in length) was about 62 %/(104 T) over the range of measurement of the magnetic field Bmeas which varied from 0 to ±5x10-4 T, under a constant value of the bias magnetic field Bbias of 20x10-4 T. Namely, it was approximately 62 times greater than that of giant magnetoresistance sensor. In addition, the present paper examined the dependence of resistivity ρ(T) on temperature, the dependence of ρ(T=77.4 K) of the sensor on current density, the dependence of Son t, and the dependence of measured resistance of the magnetic field Rmeas on Bmeas