Magnetic property characterization system employing a single sensing coil arrangement to measure both AC susceptibility and DC magnetization

摘要

A coil arrangement having a primary and two balanced secondaries is used to measure ac susceptibility and, using sample movement, also to perform absolute dc moment measurements. Since the same coil arrangement is used for both AC and DC measurements, the measurements can be made successively within a cryogenic chamber without removing the sample. This is a big advantage, because the changed conditions associated with removing and replacing a sample between measurements can cause confusing, uncorrelated results. A high speed voltmeter is used to perform the signal analysis for the moment measurement. The system can be configured to yield high resolution dc moment measurements to 25 ppm and sensitivities to better than 5x10-5 emu.