B–H Meter for Samples of Small Cross-Sectional Area

Abstract

An instrument for measurement of the magnetic properties of samples of small cross‐sectional area is described. The signal from two opposed pick‐up coils, one of which contains the sample, is integrated, amplified, and applied to the vertical deflecting plates of a cathode‐ray oscillograph. Each of the pick‐up coils lies in one of a pair of identical magnetizing solenoids. The signal from a non‐inductive resistance in series with the solenoids provides the horizontal deflection for the cathode‐ray oscillograph so that the hysteresis loop of the sample is displayed on the fluorescent screen. The instrument is well suited for measurement of the magnetic properties of samples having cross‐sectional areas of the order of magnitude of 10⁻⁵ cm².