Measurement and Gaussian model of ferromagnetic viscosity

Abstract

The exponential model of ferromagnetic susceptibility for steel has been extended to include ferromagnetic viscosity by comparing measured eddy current free susceptibility with the static exponential model. Viscous susceptibility and viscous field advance are derived from the definition of ferromagnetic viscosity. Measurements were performed on both a pipe in an isothermal yoke and a disk in a vibrating sample magnetometer. Yoke design is described and disk corrections for magnetized volume fraction and field demagnetization were computed using a quasistatic magnetization volume integral equation. Accuracy of this model suggests that the four parameters of the static model plus two parameters of the Gaussian model plus one eddy current delay parameter form a complete description of ferromagnetic hysteresis.