Magnetic Measurements

For measuring of the fundamental magnetic properties of a material (Br, bHc, iHc, BHmax, demagnetisation curve), Hysteresisgraph or BH-tracker is used. A BH-tracker consists of an iron (usually FeCo) yoke to form a closed circuit, electromagnets to create the demagnetizing field and fluxmeters to determine the demagnetizing field and the materials response.

Measurement of magnetic moment with a fluxmeter and a Helmholtz coil is a convenient way to test permanent magnet materials. Other values such as operating flux density (Bd) and residual flux density (Br) can be derived from the measured moment value. Although this method is not asaccurate as hysteresisgraph measurement, the measurement process is fast and easy, the sample don’t need to be of special shape, values are useful and reliable, and equipment cost is substantially less.