Demagnetizing correction in fluxmetric measurements of magnetization curves and hysteresis loops of ferromagnetic cylinders

A technique is proposed for demagnetizing correction of the measured magnetization curve and hysteresis loop, i.e., the M∗(Ha) curve, of a ferromagnetic cylinder into the true M(H) curve of the material, where Ha is the uniform applied field provided by a long solenoid and M∗ is the magnetization measured by a fluxmeter with the measuring coil surrounding the cylinder midplane. Different from ordinary demagnetizing correction by using a fixed demagnetizing factor, an (Ha,M∗)-dependent fluxmetric demagnetizing factor Nf(γ,χd) is used in this technique, where γ is the ratio of cylinder length to diameter, χd is the differential susceptibility on the corrected M(H) curve, and Nf(γ,χd) is approximated by accurately calculated Nf(γ,χ) of paramagnetic cylinders of the same γ and χ=χd. The validity of the technique is studied by comparing results for several samples of different lengths cut from the same cylinder. Such a demagnetizing correction is unambiguous but its success requires very high accuracy in the Nf determination and M∗(Ha) measurements.