High- thick-film magnetic field sensor based on harmonic generation effects

Abstract

The harmonic generation effect in superconducting Bi(Pb) - Sr - Ca - Cu - O screen printed thick film is reported. When an ac field of frequency 10 kHz is applied to the film, odd harmonics corresponding to frequencies 30, 50 and 70 kHz are observed. The addition of a dc field , induces the generation of even harmonics at frequencies 20, 40, 60, 80 kHz. The amplitudes of these harmonics are studied as a function of and . In the low-field region the amplitude of the even harmonics has been found to vary linearly with with the maximum amplitude change found for the second harmonic. The development of a high- thick film magnetometer based on the measurement of the amplitude of the second harmonic is described. The sensitivity of this magnetometer has been found to depend on and on the frequency of the ac field. The lowest field noise was found to be T.

Surface nucleation and domain growth mechanism in NdBCO thick films on YSZ substrates

“…Other types of applications are devices that depend on the microwave properties of the superconductor such as antennae, resonators and filters [2]. Moreover, Khare et al [3] have used a superconducting thick film in the fabrication of a magnetometer based on harmonic generation effects with a field sensitivity ≈1.5 × 10 −8 T. Although the field sensitivity of a thin film high-T c SQUID is better, the thick film magnetometer is very simple, requiring no patterning.…”

A novel method for sensing rotational speed, linear displacement and current using superconducting BPSCCO magnetic sensor

“…However, superposition of a small d.c. field breaks this symmetry and brings the appearance of even harmonics. Amplitudes of the even harmonics are found to be a strongly linear function of applied d.c. field (Ghatak et al 1992;Khare et al 1997;Dey et al 1999).…”

“…The origin of the harmonic generation and its modulation with d.c. magnetic field is explained elsewhere (Xenikos and Lamberger 1990;Muller 1990;Qin and Ong 1999). The observed linear dependence of the amplitude of the second harmonic response with low d.c. magnetic field can be exploited as a highly sensitive magnetic field sensor (Gallop et al 1988(Gallop et al , 1989Khare et al 1997;Dey et al 1999). Magnetic sensors, with the capability of sensing very low magnetic fields are of great technical and commercial significance.…”

A sensitive magnetic field sensor using BPSCCO thick film

“…Discovery of high temperature superconductors have opened up newer possibilities for their applications in the fabrication of magnetic shields (Itoh et al 1997), magnetic bearings (Itoh et al 1989) as well as various types of detectors (Zheng et al 1990;Wise et al 1993) and sensors (Villegier et al 1991). Apart from the most sensitive of all existing magnetic sensors (the SQUIDs), the magnetic sensors based on the second harmonic response of magnetic susceptibility (Gallop et al 1989;Gielisse et al 1991;Khare et al 1997;Dey et al 1999), those based on the sharp jump of trapped magnetic flux (Rostami et al 1998) as well as, on the microwave properties (Kirschner et al 1994) of bulk and thin films of ceramic superconductors have been proposed. Of these the magnetic field sensors based on the 2f response of weak links present in high temperature superconductors are capable of detecting of field in the range from 10 -4 T to 10 -8 T and they are expected to find applications for non destructive evaluation of cracks in ferromagnetic plates etc (Buckley et al 1991).…”