Application of the mixing of the field of low amplitude AC bias with a strong field of linear slow varying to investigate the magnetic properties of materials

The paper presents a new experimental method of the magnetic hysteresis loop investigation and the constructed measurement instrument. The principle of operation is to mix two magnetic fields: the first of these fields has a very low amplitude, a shape of sine wave (AC bias) and the frequency range order of 10–10⁴ Hz. The second field has a very low frequency (order 10⁻² Hz), a high amplitude and forms approximately a triangle wave. The presented, dedicated system is different in comparison to commonly used hystographs and it consists of coreless coils only. The measurement method gives the opportunity of obtaining more detailed measurements of the initial cycles in the material magnetizing process. In a special case, the magnetic field strength changes in the B(H) curve can be stopped at any operating point and then it is possible to investigate local properties using AC bias field for various frequencies. The results revealed a successive displacement of the hysteresis loop and approaching to the steady state position.