METHOD AND APPARATUS FOR ESTIMATING CLOSED-CIRCUIT HYSTERESIS CURVES FOR MAGNETIC MATERIALS

摘要

A method for calculating the closed-circuit full-loop hysteresis curve of a permanent magnet sample is presented. The method combines a mathematical model of the sample with measurements from a Pulsed-Field Magnetometer (PFM) or other open-magnetic-circuit measurement technique. The model is used to find the minimum-energy configuration of dipoles within the sample. Appropriate Hamiltonian parameters are adjusted to best-fit the open-circuit hysteresis loop to the open-circuit measurement. Periodic boundary conditions are then applied to model the closed-circuit environment. The closed-circuit-like characteristic is obtained by running the model with periodic boundary conditions and the best-fit parameters from the open-circuit data. The calculated closed-circuit-like full-loop hysteresis curve has been shown to more closely match the measured closed-circuit curve obtained by a permeameter compared as against an SDF correction.