Research On Flexible Strain And Magnetic Sensor Based On Magnetic Amorphous Wire

With the rise of smart wearable devices,flexible electronic devices have attracted widespread attention due to their advantages of being light,thin,comfortable,low energy consumption,and high biocompatibility due to their conformal attachment to the human body.As a channel to obtain human health information,flexible sensors have become an important part of flexible electronic systems.Human health information includes exercise/physiological parameters such as joint movement,ECG,and respiration,as well as in vitro environmental information such as magnetic field and temperature.The development of a multi-functional flexible sensing system with both exercise/physiological parameter monitoring and in vitro environment sensing is the key to realizing the digitization of health information.The important parameters of human health,such as joint movement and respiration,are closely related to strain;and the perception of magnetic field can endow human beings with the "sixth perception" function,which plays an important role in the field of magnetic field early warning and human-computer interaction.Therefore,the development of flexible strain-magnetic field multifunctional sensors is one of the important ways to realize the digitization of health information.Co-based magnetic amorphous wire has the advantages of good flexibility,high magnetic permeability and excellent giant magneto-impedance effect,making it an ideal sensitive material for the preparation of flexible strain-magnetic field multifunctional sensors.Based on this,a flexible magnetic sensor with low detection limit and wide range is constructed in this paper.In order to further achieve elasticity and multi-functionality,a self-powered high elastic strain/magnetic field sensor and a self-decoupled strain magnetic field dualmodal sensor were developed.The main contents and conclusions of the paper are as follows:1.Aiming at the problem that the current magnetic sensor is difficult to be compatible with low detection limit and wide range under a single device,a cantilever beam structure was designed using Co-based magnetic amorphous wire,and a flexible magnetic sensor with both low detection limit and wide range was prepared.Using the giant magneto-impedance effect of amorphous wire,magnetic field detection down to22 nT is achieved.The stress conversion unit based on magnetic particles bends the cantilever beam under the action of the magnetic field and changes the angle between the amorphous wire and the magnetic field.Using the difference of the giant magnetoimpedance effect in the longitudinal and vertical directions,the maximum magnetic field of 0.4 T can be detected.The flexible magnetic sensor has a detection limit of 22 nT and a range of 0.4 T,which effectively expands the application field of amorphous wire-based magnetic sensors.2.In view of the current problems of complex integration of flexible sensor batteries and difficulty in power supply,Co-based magnetic amorphous wire is used as the magnetic core of liquid metal-based inductive coil to construct an elastic selfpowered strain/magnetic field sensor.The sensor realizes the detection of large deformation(200%)and large magnetic field(200 m T).In addition,the deformation of the sensor itself or the change of the external magnetic field leads to the change of the magnetic flux of the coil.Based on the Faraday electromagnetic induction effect,a voltage/current will be generated spontaneously,so as to achieve a high current output(maximum 2 m A).The sensor has the characteristics of large stretching range,selfpower supply,low internal resistance,high current,etc.,and shows broad application prospects in wearable electronic devices.3.Aiming at the problem that it is difficult to achieve decoupling of various signals in the current multi-function sensor,the self-decoupling function of the DC signal(resistance)and the AC signal(inductance)of the liquid metal inductance coil based on the Co-based magnetic amorphous wire core is designed.A self-decoupled dual-modal strain/magnetic field sensor was fabricated.The coil’s DC resistance is used to sense the strain of the sensor,and the coil’s AC inductance is used to sense the environmental magnetic field and strain.Establish mathematical models and equations to realize the decoupling of strain and magnetic field signals under 0-10% strain and 0-10 Oe magnetic field.And applied to the real-time monitoring of finger state,it provides a new way for the application of flexible electronic devices in virtual reality,humancomputer interaction and other fields.