Digital M-H plotter for low-coercivity metallic glasses

A computer-based system for plotting the DC magnetisation loops of amorphous magnetic ribbons is described. The system overcomes the problems associated with very low coercivity materials by using a nonlinear H-field function that can be adjusted for a particular loop. The problem of drift is overcome by the use of a hybrid analogue/digital integrator and software correction. Commonly used magnetic parameters are calculated from the digitised data. In particular, coercivities of less than 1 A m -1 can be reliably measured. Typical results are presented to illustrate the performance.