Environment Stability Of Piezomagnetic Properties Of Fe-based Amorphous Alloy Films

The sensor is facing this complex and changeable environment when it is used in practice.As a sensor sensor element,Fe-based amorphous alloy thin film must keep its performance stable in various complex and changeable environments.It is of great significance to study the piezomagnetic stability of Fe-based amorphous alloy films and to improve the piezomagnetic stability of the films by annealing to adjust the internal stress state of the sensitive films.In this paper,the environmental stability of the piezomagnetic properties of amorphous alloy films Fe₇₈Si₁₃B₉ and Fe_73.5Cu₁Nb₃Si_13.5B₉ has been studied by direct measurement of the piezomagnetic properties of amorphous alloy films,in the stress range of 0¹kPa.In the range of 0¹ kPa,under the environment of 15 C and 40%R.H,the Fe₇₈Si₁₃B₉ film exhibit positive piezomagnetic.Negative piezomagnetic phenomenon occurs after annealing the Fe₇₈Si₁₃B₉ film at 350°C.The stress sensitivity of Fe₇₈Si₁₃B₉film is small,but the linear relationship with the loop inductance value and the applied stress is very stable.The Fe_73.5Cu₁Nb₃Si_13.5B₉ amorphous alloy film exhibits a negative piezomagnetic phenomenon.The reproducibility of the Fe_73.5Cu₁Nb₃Si_13.5B₉ film annealed at 200°C is the best.The influence of ambient temperature on the piezomagnetic properties of Fe₇₈Si₁₃B₉ amorphous alloy films and Fe_73.5Cu₁Nb₃Si_13.5B₉ amorphous alloy films is significant.The piezomagnetic sensitivity of Fe₇₈Si₁₃B₉ amorphous alloy films increases with the increase of ambient temperature,and reaches its maximum when the temperature rises to 50 C.The ambient temperature has an effect on the piezomagnetic effect sensitivity of Fe_73.5Cu₁Nb₃Si_13.5B₉ amorphous alloy films.The piezomagnetic effect and sensitivity stability are the best in the range of 20-30?.The piezomagnetic effect sensitivity|SI|_max values of Fe₇₈Si₁₃B₉ and Fe_73.5Cu₁Nb₃Si_13.5B₉ amorphous alloy films are the largest,when the ambient humidity is 30%R.H.The ambient humidity has different effects on the piezomagnetic properties of the two films,but no obvious change rule has been found so far.Therefore,it is better to package them in the later use process to avoid measurement errors.Fe₇₈Si₁₃B₉ and Fe_73.5Cu₁Nb₃Si_13.5B₉ amorphous alloy films have positive and negative piezomagnetic effect transformation under certain conditions.