Weak magnetic field response characteristics of magnetostrictive materials

Based on the application requirements of magnetostrictive materials in weak magnetic field sensor, the magnetic field response sensitivities of Tb-Dy-Fe material and Fe-Ga alloy were measured by using Michelson interferometory. The magnetic field and temperature responses of Fe-Ga alloy under different external stresses were also experimentally analyzed in detail. The experimental results show that when the magnetic induction is about 16 mT in the condition of no external stress, the magnetic field response sensitivity of Fe-Ga alloy is much higher than that of Tb-Dy-Fe material. For the magnetic sensors requiring high sensitivity and small measurement range, Fe-Ga alloy are more suitable as the sensitive material of the sensors. Especially, under 1.2 MPa external stress and 26 mT offset magnetic field, Fe-Ga alloy will exhibit preferable magnetic field response sensitivity and larger saturation magnetostriction coefficient, which can be considered in the optimal working state. Therefore, the measured magnetic field and temperature responses curves of those materials could be used as the parameter design references of weak magnetic field sensors.