Development of a thin-film high-temperature superconductor Hall magnetometer

Abstract

We have developed and investigated a thin-film Hall sensor coupled with a high-T C superconducting antenna structure. In this paper we present a theoretical model from which we can derivate the criteria for the layout and the technological realization of the sensor system. The model describes the improvement in the sensitivity of the magnetometer system by a superposition of the external field and an inductive incoupling of a field generated from the superconducting antenna. Based on the theoretical results it is possible to realize a hybrid magnetometer with a sensitivity of about 2.3 V T −1 and with a field resolution of about 1 nT Hz −1/2 at a temperature of 77 K.

Hybrid magnetometers for unshielded operation : combining hall sensors with superconducting flux concentrators

“…Compared to the work of Schmidt et al [46] doped Si has a higher Hall coefficient compared to Bi. This is beneficial since the sensitivity of the Hall sensor is linearly dependent on the Hall coefficient.…”

“…Due to the local high current density the magnetic field in the vicinity of the constriction is also increased and that is where a sensor can be placed. Dependent on the sensitive direction of the sensor (in plane or perpendicular) the sensor can be placed on top of, or next to the constriction [46][47][48][49][50]. Note that both possible sensor positions are displayed in figure 1.3b).…”

“…The effective field on the sensor B y,eff is given by the integral of the field over the width of the sensors: we assume a strip with width 2s from −s to s as displayed in figure 3.3 carrying a I scr homogeneously distributed over the cross section of the strip. The field next to the strip B y (z) is [46]:…”

“…The work in this chapter is motivated by applications of high-T c superconducting sensors such as superconducting quantum interference devices (SQUIDs) [60] and hybrid magnetometers based on high-T c flux concentrators [46]. These sensors are used in a broad field of applications, such as geophysical research [61] and biomagnetism [62].…”

“…Reports have been made about a high temperature superconductor Hall magnetometer based on a bismuth (Bi) Hall device and YBa 2 Cu 3 O 7−δ (YBCO) flux concentrators [46,47]. These devices can reach a maximum sensitivity of 2.3 VT…”