Research On Cantilever Magnetic Field Sensor Based On Giant Magnetostriction Film

As a new type of material,giant magnetostrictive materials have been paid more attention by researchers,and researchers focus on the sensors designed by magnetostrict ive effect.In thesis,based on the magnetostrict ive effect of giant magnetostrict ive materials,combined the giant magnetostrict ive material wit h the cant ilever beam structure,and studied it magnet ic field measurement performance.In thesis,the static deflect ion and resonance frequency of the cant ilever beam coated with giant magnetostrict ive film under magnet ic field are analyzed,in order to avoid the tedious description,the cant ilever beam coated with giant magnetostrict ive film is referred to as coated cant ilever beam,and deduced the relat ionship between the static deflect io n and resonance frequency wit h magnet ic field strength and magnetostrict ion coefficient.And obtain the formula of the coated cantilever beam's sensit ivit y for measuring the magnet ic field in stat ic deflect ion mode and resonant mode.Simulat ed the coated cantilever beam which fixed at one end by ANSYS finit e element simulat ion software,the structural dimensio ns of the coated cant ilever beam are: 8000?m long,800?m wide,30?m thick of the giant magnetostrict ive film and 100?m thick of the substrate cant ilever beam.And obtained the average sensit ivit y of measuring magnet ic field under static magnet ic deflect ion mode is 0.283?m/(k A/m).The average sensit ivit y of measuring magnet ic field under resonant operating mode is 4.890 Hz/(k A/m),The maximum sensit ivit y is 9.500Hz/(k A/m).In thesis,the coated cant ilever beam is prepared by magnetron sputtering method,the process parameters during prepar at ion were sputtering gas pressure 0.5Pa,substrate temperature 20°C,sputtering power300 W,sputtering time 25 h,and the coated cant ilever beam was subjected by vacuum heat treatment.The size of the coated cant ilever beam which prepared are 85 mm lo ng,5mm wide,6?m thick of the giant magnetostrict ive film and 128?m thick of the substrate cantilever beam.Measured the static deflect ion and resonance frequencies of the prepared coated cant ilever beam,because the coated cant ilever beam need to fixed one end during the time of measurement,so the actual measured length is 76 mm,the static deflect ion and resonance frequency under magnet ic field were measured by capacitance method.According to the measured amount of static deflect ion,the magnetostrict io n coefficient of prepared giant magnetostrict ive film can be calculated.The average sensit ivit y of the coated cant ilever beam in the static deflect ion mode is 2.010?m/(k A/m),the maximum sensit ivit y is 2.818 ?m/(k A/m).When the magnet ic field intensit y is 0(k A/m)to 5(k A/m),the measured resonance frequency decreased wit h the increase of the magnet ic field intensit y,this is because of the ?E effect.The sensit ivit y of magnet ic field measurement under the resonant working mode of the coated cant ilever beam is obtained as follows: The average sensit ivit y of the magnet ic field intensit y is0.006Hz/(k A/m)between 0(k A/m)and 5(k A/m).The average sensit ivit y o f magnet ic field intensit y above 5(k A/m)is 0.217Hz/(k A/m).