Single-axis Helmholtz coil
The simple, economical solution that never goes out of style.
Helmholtz coils provide an easy and non-destructive way to control the quality of permanent magnets. The Helmholtz coils can be single-axis or 3-axis. The triple-axis version lets you see the direction of the magnetization with respect to the axes, regardless of how you place the magnet. The complete system to perform this measure consists of a single-axis Helmholtz coil and just a fluxmeter.