Frequency and temperature dependencies of the switching field in glass-coated FeSiBCr microwire

• Strong temperature dependence of the switching field was observed in FeCrSiB amorphous glass coated microwires.
• The switching field variation is as high as almost 200% in the temperature range 125–425 K.
• The linearity of the temperature dependence is not influence by the frequency of applied field.
• Such a behavior gives possibility to employ the FeCrSiB microwires as a very sensitive temperature sensor.

We have studied frequency and temperature dependencies of the switching field in amorphous Fe67.5Si7.5B15Cr10 microwire. Three different regions in the frequency dependence were identified. A decrease of the switching field at low frequencies up to 50 Hz is explained in terms of structural relaxation. Above 50 Hz, the magnetoelastic contribution of the switching field is dominant which can be fitted by a power law (Hswσ–f1/n) with the exponent n equal to 1.5 and 1.0 for frequencies below and above 1900 Hz, respectively. Regarding the temperature dependence, at low temperatures below 150 K, the switching field is high and weakly temperature dependent. However, above 150 K the switching field decreases. The high structural stability and the almost linear variation of the switching field with temperature makes the investigated amorphous microwire a suitable candidate as miniaturized temperature sensor for working in a wide temperature range from 150 K up to 425 K.