Alternating gradient force magnetometry: Applications and extension to low temperatures (invited)

Abstract

This paper describes the results of a study undertaken to determine the sensitivity and reproducibility of a commercially produced alternating gradient force magnetometer. A noise base of 2×10-8 emu is achievable with an averaging time of 1 s. Reproducibility was found to be within 6% for most samples, but increases to 20% with low moment samples. The effect of the alternating field gradient on magnetic measurements has been fully investigated. The alternating field gradient is found to have significant effects on samples with a low fluctuation field and low coercivity. A low temperature system (4-300 K) is described and modifications to improve the sensitivity and base temperature are discussed.