Giant magnetoelectric effects in serial-parallel connected Metglas/PZT arrays with magnetostrictively homogeneous laminates

Abstract

To ensure the magnetostrictive softness, the homogeneity, the decrease of the shear-lag effect and the space-saving construction of narrowed longitudinal-transverse L-T magnetoelectric (ME) composites, a novel parallel-connected-multi-bars (PCMB) geometry of PZT/Metglas is proposed and investigated by simulation and experiment. In this case, Metglas layers are structured in different geometries from the conventional single bar (c-SB) to conventional separated multiple bars (c-SMB), elongated separate multi-bar (e-SMB) and n-magnetic-bar based PCMB (n-PCMB). This n-PCMB geometry divides the conventional ME configuration into n parallel-connected ME units (n-PCMEU) according to the magnetic geometries. The optimal ME performance with the largest ME voltage coefficient α_E of 630 V/cm.Oe is achieved in PCMEU with two Metglas bars (n = 2). The ME voltage coefficient can be further enhanced by integrating m of these optimal PCMEUs in series to form a serial-parallel ME unit array m-S (n-PMEU)A. The α_E value increases by a factor of 3.6 and reaches 2.238 kV/cm.Oe for 4-S (2-PMEU)A, a factor that is almost equal to m. The resulting 4-S (2-PMEU)A sensor possesses an extremely high sensitivity of 18.1 μV/nT, with a resolution of 10⁻¹ nT.