Magnetoelastic Humidity Sensors with TiO(2) Nanotube Sensing Layers

In this study, TiO(2) nanotubes (TiO(2)-NTs) are coated with a drop-casting method on Fe(40)Ni(38)Mo(4)B(18) amorphous ferromagnetic ribbons and the humidity response of the prepared magnetoelastic sensors (MES) is investigated. The synthesis of TiO(2)-NTs is performed using a hydrothermal process. Sample characterization is carried out using X-ray diffraction and scanning electron microscopy. The results show that the sensors can measure moisture values in the range of 5% to 95% with very high precision and very low hysteresis. The humidity variation between 5% and 95% shows a change in the sensor resonance frequency of ~3180 Hz, which is a significant change compared to many magnetoelastic humidity sensors developed so far.