## 3 Results and Discussion
### Measurement of Magnetic Hysteresis Curve of Magnetometric Relax-Type Probe Core  
In order to demonstrate a wide variety of the proposed measuring station utilization, the magnetic hysteresis curve of another sample made of metallic alloy is presented. The investigated sample corresponds to an open-ended core used as a sensing element of a relax-type fluxgate magnetometer magnetometric probe. The purpose of measuring the  
Figure 6: Comparison of the magnetic hysteresis curves of the magnetically soft ferromagnetic core measured by two different methods. magnetic hysteresis of the magnetometric probe core is generally based on the need to determine its magnetic properties in order to objectively assess its potential use in the given application before final production. The magnetometric probe core was produced from the eight identical Co-based amorphous ribbons, VITROVAC 6025, assembled into a single prismatic core, with total dimensions of 80 \(\times\) 2 \(\times\) 0.2 mm. Since the dimensions of the probe differ in comparison to the previously discussed actuator core, so does its total volume, which equals 25.6 mm\({}^{3}\). In the case of the magnetometric probe core, a smaller volume represents a more desired solution due to the higher sensitivity to the measured magnetic field. Conversely, a higher volume is a preferable option regarding the actuator core since the high magnitude of generated magnetic moment is required to acquire a fast response to sudden changes in position. Before the initialization of the measurement, the same demagnetization procedures designed to remove the residual magnetization of the measured sample were performed, as well as the workstation configuration intended to optimize the measuring process. Due to a smaller sample volume, the excitation current was set to a value of 52,428.8 bits, which corresponds to 1 A. Since the length of the sample is equal to 80 mm, the distance between the sensitive point of the probe and the center point of the core was again 157.064 mm during the measurement to comply with a condition of the used measurement method--\(I/2r\leq 1\). The measurement was performed with a defined step of 100 bits (524 measuring points). At each given set value of excitation current, the 200 samples of the stray magnetic field of the magnetized core were measured to compress inducted measurement uncertainties. The measured magnetic hysteresis curve of the investigated magnetometric probe core is shown in Figure 7.  
As can be seen, the measured hysteresis corresponds to a magnetically soft material with an amplitude of 0.6 T in the saturated state. The large linearity, low residual magnetization, and magnetically soft nature giving a small coercivity (approximately 32.2 A/m) are preferable options regarding the magnetometric relax type probe since fast relaxation to the area of initial permeability is required for the magnetometric applications. In comparison to the actuator core, the hysteresis curve of the probe core reaches a higher slope of a linear part (see Figure 7), which equals the value of 0.00365 approximately (the slope of the actuator core is for the same point equal to the value of 0.000127). This effect is caused by the smaller ratio of the cross-sectional area of the core to its total length, which leads to the manifestation of the smaller demagnetization fields that suppress the excitation magnetization field during the magnetization process. In Figure 7, it is also possible to observe the induced noise appearing, especially in core saturation. These sudden fluctuations in magnetic polarization are caused by the magnetized core's low generated magnetic moment, which results in the formation of weak stray magnetic fields. The low magnitude of the magnetic flux density of the stray magnetic fields of the core is then more significantly influenced by the core's noise and the noise of the surrounding environment.