A permeagraph (also called hysteresisgraph) is a closed-loop measuring system for characterization of bulk magnetic materials of well-defined shapes.
Hysteresisgraph at the Istituto di Struttura della Materia, Roma, IT (ISM-CNR)
Example of scientific results:
Demagnetization curve (in red) at room temperature of a strontium ferrite permanent magnet.
(Istituto di Struttura della Materia, Roma, IT (ISM-CNR))