Hystograph HG 200

Magnetic measurement techniques give deeper insights into important properties of magnetic materials. Even if today many problems can be described with numerical methods, measurement of the magnetic properties of magnetic components and systems remains indispensable. In addition, simulations are based on material data, which must first be determined by measurement.

The response of magnetic materials can vary greatly with applied magnetic field. To measure desired characteristics, a controlled magnetic field must be applied. A commonly used instrumental setup facilitating the measurements is a hystograph.

With a hystograph, the demagnetization curves and complete hysteresis loops of semi-hard and hard magnets can be recorded automatically. The measuring method is standardized and validated by comparative measurement.

Measurement principle

The central component of the measuring device is an electromagnet in which the sample is magnetized and demagnetized in order to pass through the hysteresis loop. The magnetic field strength H and the magnetic polarization J are measured simultaneously with special measuring coils. Two integrators (fluxmeters) are required for this purpose. The recording of the measurement data and the control of the power supply for the electromagnet is controlled by a computer. This allows an evaluation of the measured data, so that, among other things, the following parameters are directly available:

B_r [T] … remanence

H_cJ [kA/m] … coercive field strength

(BH)_max [kJ/m³] … maximum energy density

M_s [kA/m] … saturation magnetization