Fabrication and Characterization of an Integrated 9-Channel Superconducting Quantum Interference Device Magnetometer Array

Abstract

We have fabricated and characterized nine Superconducting Quantum Interference Device (SQUID) magnetometers, which were integrated on a single chip. The magnetometers are based on a directly-coupled multiloop SQUID with Nb Al AlO x Nb junctions, and are arranged in a 3 3 matrix in the area of 10 mm 10 mm. The diameter of the circular pick-up loop of each magnetometer is 2.5 mm and the distance between neighboring magnetometers is 2.75 mm. In the operation with a flux locked loop (FLL) with direct voltage readout, typical flux-locked noise level of less than 3 10 6 8 0 Hz in the white region were obtained with the magnetometer in a superconductive shield. From the calibration of the sensitivity, typicalfield noise was measured to be 7 fT Hz. In combination with a small cryostat, we expect that this magnetometer will be useful for multi-channel measurement of magnetic fields requiring highly spatial resolution in various applications.

Volcanic ash in bare ice south of Sør Rondane Mountains, Antarctica: geochemistry, rock magnetism and nondestructive magnetic detection with SQUID gradiometer

“…Second, anhysteretic remanent magnetization (ARM) was imparted in DC magnetic field of 50 mT and AC magnetic field of 80 mT, then the samples were stepwise demagnetized with AC magnetic field of 0, 5, 10, 15, 20, 30, 40 mT. A three-axis LTS-SQUID gradiometer at KIT was used to measure magnetic gradients in three axes just above tephra-bearing ice block samples and model samples. The gradiometer is based on Nb/AlAlOx/Nb Josephson junctions with a flux transformer (Jacox and Ketchen 1981), which was fabricated on a 5 mm × 5 mm silicon chip using the similar thin-film processing described in Kawai et al (2005). The gradiometric planar pickup coil, which is also integrated on the same chip, has the area of 1.5 mm × 1.5 mm with the baseline of 3 mm (Fig.…”

Micro-Magnetocardiography System With a Single-Chip SQUID Magnetometer Array for QT Analysis and Diagnosis of Myocardial Injury in Small Animals

“…This array has a 2.5-mm diameter pickup coil on each sensor, and is arranged in a 3 3 square matrix with a distance of 2.75 mm between each coil [5].…”

Development of a biomagnetism measurement system for small animals

“…The integrated sensor has nine of 2.5 mm diameter pickup coils, and which are arranged 3 × 3 square matrix with 2.75 mm distance between each coil [4]. The sensor covers an area of 8 mm × 8 mm which is adequate for MEG/MCG measurements of small animals.…”