Characteristics of a bulk BPSCCO magnetic sensor constructed by the shock compaction method: Effect of the shock compaction pressure on magnetic sensitivity

Recently, there has been an increased need for the development of a highly sensitive magnetic sensor for gathering new magnetic information. As one of the basic areas of research for the development of a highly sensitive magnetic sensor, the present authors have constructed a bulk Bi-Pb-Sr-Ca-Cu-O (BPSCCO) magnetic sensor by the shock compaction method as a new fabrication technique of the bulk high-critical temperature superconductor (HTS). Values of the shock compaction pressure P are systematically changed between 1 and 9 GPa to investigate the magnetic sensitivity S of the sensor. It was found that the value of S was related to the value of P. The magnetic sensitivity reached optimum values when maintaining a pressure of 1 GPa, being approximately 11%/(10(-4) T), and about 11 times that of a giant magnetoresistance (GMR) sensor. The voltage fluctuation of a bulk BPSCCO sensor, when changing the value of P, under a constant current density J, was previously unknown. To help clarify this, systematic measurements were taken of the voltage noise power (VNP) spectrum of the sensor. The results lead to an important criterion for use in the design of a highly reliable and sensitive magnetic sensor.