High sensitive nonlinear modulation magnetoelectric magnetic sensors with a magnetostrictive metglas structure based on bell-shaped geometry

•A novel dumbbell shape was designed for metglas.•The ME charge coefficient was enhanced to 2600 pC/Oe based on a dumbbell-shaped metglas.•An active mode nonlinear system for ME sensor was established to detect magnetic signals.•Via modulation, the sensitivity was enhanced to 80 pT/√HzpT/√Hz.•The sensitivity of the nonlinear ME sensor increases as the width of end-flange increases.

In this paper both linear and nonlinear magnetoelectric (ME) effects have been investigated intensively. In order to obtain magnetic amplification, we fabricated 3 multi-push–pull mode magnetoelectric laminated composites metglas/PMNT/metglas based on dumbbell-shaped metglas. The linear magnetoelectric charge coefficient is enhanced to 2600 pC/Oe at 2 Hz based on dumbbell-shaped metglas and it increases as the end-flange width of the dumbbell-shaped metglas increases at 2 Hz, respectively. Based on these 3 ME composites, we establish an active mode nonlinear modulation system for ME magnetic sensor, the sensitivity of which are enhanced to 80, 100 and 102 pT/√HzpT/√Hz at 1 Hz for the composites with the end-flange width 20, 15 and 10 mm, respectively, via nonlinear ME　modulation method. Strain distribution simulations illustrate the theoretically accurate amplification of the dumbbell-shaped geometry. The center strains of 3 dumbbell-shaped metglas decrease as the width of end-flanges decreases