Preparation and characterization of AlN/FeCoSiB magnetoelectric thin film composites

The preparation process of AlN/FeCoSiB thin film composites has been studied in detail in this work. The results indicate that annealing is more effective to improve the intensity of AlN (002) peak compared with changing sputtering parameters. After annealing at 500 °C, the AlN film possesses the highest intensity of (002) peak, typical columnar microstructure and root-mean-square (rms) roughness of 5 nm. The coercivity (Hc) of FeCoSiB film decreases significantly after annealing in magnetic field. After annealing at 350 °C, a minimum Hc of 2.6 Oe is obtained in FeCoSiB film, contributing to the achievement of most pronounced magnetic field sensitivity. The magnetoelectric (ME) voltage coefficient αME up to 101 V/cm Oe is obtained at DC bias magnetic field (Hdc) of 10 Oe and at the frequency (f) of 1 kHz. Furthermore, the thin film composites display an AC magnetic field sensitivity of 1.6 nT/√Hz at 1 kHz.