High Sensitivity Faraday Susceptibility Apparatus

Abstract

A high sensitivity Faraday susceptibility apparatus employing a quartz beam microbalance is described. With this apparatus, it is possible to measure the susceptibilities of small samples (0.2 mg) and adsorbed gases, to adequately account for ferromagnetic impurities by the Honda-Owen method, and to carry out measurements over a range of ambient atmospheres and temperatures (80–700°K). An automated null technique was developed for continuous operation in time dependent studies. In practice, the error obtained with this apparatus is 0.1% for precision and ≤1% for accuracy and it is possible to obtain, under favorable conditions, an ultimate sensitivity of ±0.001×10−6 emu/g.