Highly-sensitive analog magnetometer based on a null-picovoltmeter

Abstract

The principle of measurement of small magnetic moments using superconducting null-picovoltmeter (SNPV) is described. It is shown that in the mode with optimal voltage sensitivity (≥10^–12 V), the sensitivity of SNPV to a magnetic moment can reach 10^–8 emu, the level only implemented in SQUIDs. An example is given of using SNPV to measure the magnetic susceptibility of superconducting diamagnetic and paramagnetic samples, approximately 1 mm³ in volume, with different signs of the magnetization in the magnetizing alternating magnetic fields with induction of about 1 G, at low temperatures.