Effects of Core Dimensions and Manufacturing Procedure on Fluxgate Noise

The effect of demagnetizing factor and manufacturing procedure on noise of the fluxgate probes, manufactured from metallic glasses, is presented. The fluxgate probes were either tape-wound, or flat, wet-etched ringcore and race-track geometries. When combining low demagnetizing factor and high enough cross-section of the probe, a minimum in the noise dependence can be found. For 50 mm ringcores, in such minimum the noise value as low as $7 pT_{RMS}$ in 0.1-10 Hz frequency band was achieved, which is very low for an as-cast tape, and has not been reported before.