The direct observation of magnetic images in electromagnet vibrating sample magnetometers

Hoon, Steve R. and Willcock, S N M (1988) The direct observation of magnetic images in electromagnet vibrating sample magnetometers. Journal of physics e: scientific instruments, 21 (5). pp. 480-487. ISSN 0022-3735

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Abstract

The authors report incontrovertible evidence of the first direct observation of ferromagnetic images in iron-core electromagnet vibrating sample magnetometers (VSMs) and determine their magnitude. They demonstrate experimentally that the ferromagnetic image strength at low field approaches that of the magnetic sample source moment and find image contributions of up to 25% in one typical VSM system studied. Quadrature image formation in nonmagnetic (Cu) plates in the proximity of the detection coils and pole pieces is also investigated. As a consequence of the observations reported it is clear that failure to account for images in electromagnet VSMs can lead to underestimating the induced signal by up to 100%.