Ultra-low anisotropy magnetoelectric sensor in ferrite/piezoelectric toroidal composites

An ultra-low anisotropy magnetoelectric (ME) magnetic field sensor consisting of strictly concentric toroidal nickel-zinc ferrite/piezoelectric composite with toroidal solenoid was developed, and its sensitivity and resolution under different angles of planar AC/DC magnetic field were systemically characterized. The experimental results demonstrate that the induced voltage output strength was constant along the angles between the ME magnetic sensor and the planar DC/AC magnetic field due to toroidal structure had ultra-low shape-induced anisotropy. Consequently, for the DC case its sensitivity and resolution could reach about 15 mV/Oe and 2 x 10(-7)T under a low excitation of integral=111.42 kHz circumferential AC magnetic field, respectively. Correspondingly, for the AC case its sensitivity and resolution could reach about 56.9 mV/Oe and 7 x 10(-9)T under a 2.25Oe circumferential DC bias magnetic field. These findings provided more flexibility of the device design for weak magnetic field detection.