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

Highlights: • A technique of demagnetizing correction for M(Hcurves of ferromagnetic cylinders is proposed. • Accurate fluxmetric demagnetizing factor as a function of differential susceptibility is used. • Samples of different lengths cut from the same cylinder are studied to show the techinique validity. A technique is proposed for demagnetizing correction of the measured magnetization curve and hysteresis loop, i.e., the $M^{\ast }\left(H_a\right)$ curve, of a ferromagnetic cylinder into the true $M\left(H\right)$ curve of the material, where $H_a$ is the uniform applied field provided by a long solenoid and $M^{\ast }$ 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 $\left(H_a\text{,}{M}^{\ast }\right)$-dependent fluxmetric demagnetizing factor $N_f\left(\gamma \text{,}{\chi }_d\right)$ is used in this technique, where $\gamma$ is the ratio of cylinder length to diameter, ${\chi }_d$ is the differential susceptibility on the corrected $M\left(H\right)$ curve, and $N_f\left(\gamma \text{,}{\chi }_d\right)$ is approximated by accurately calculated $N_f\left(\gamma \text{,}\chi \right)$ of paramagnetic cylinders of the same $\gamma$ and $\chi ={\chi }_d$. 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 $N_f$ determination and $M^{\ast }\left(H_a\right)$ measurements.