Enhanced Magnetic Field Sensitivity in Magnetoelectric Composite Based on Positive Magnetostrictive/Negative Magnetostrictive/Piezoelectric Laminate Heterostructure
Resonance magnetoelectric (ME) responses are investigated for the ME laminate heterostructure consisting of positive magnetostrictive material FeCuNbSiB, negative magnetostrictive material Ni and piezoelectric material PZT-8. On one hand, both a built-in magnetic field induced by the strong magnetic interactions between positive magnetostrictive and negative magnetostrictive materials and an intrinsic anisotropic field with obvious hysteresis and remnant magnetization in Ni layer result in a large zero-biased ME effect. The corresponding zero-biased ME voltage coefficient reaches 10.12 V/Oe (126.5 V/cm Oe), which is about 3 times larger than that of traditional Ni/PZT-8 (NP) laminate. On the other hand, the additional stress produced by the high magnetic permeability FeCuNbSiB layer enhances the magnetostriction of Ni layer and ME response. The corresponding maximum ME voltage coefficient (dV<sub>ME</sub>/dH<sub>ac</sub>) is 12.09 V/Oe (150.87 V/cm Oe) at bias magnetic field <inline-formula> <tex-math notation="LaTeX">$H_{\mathrm {dc}} = 4$ </tex-math></inline-formula> Oe. It is further found that even a step change of ac magnetic field less than 10<sup>−10</sup> T can be clearly distinguished by the proposed ME composite. The value of ME voltage sensitivity to dc magnetic fields (dV<sub>ME</sub>/dH<inline-formula> <tex-math notation="LaTeX">$_{\mathrm {dc}})$ </tex-math></inline-formula> reaches ~76.7 mV/Oe at <inline-formula> <tex-math notation="LaTeX">$H_{\mathrm {dc}}= 5$ </tex-math></inline-formula> Oe and <inline-formula> <tex-math notation="LaTeX">$H_{\mathrm {ac}} =0.1$ </tex-math></inline-formula> Oe. Correspondingly, the proposed laminate heterostructure is able to possess both strong ac and dc magnetic field sensitivities.