Magnetoelectric Effects in Ferromagnetic/Piezoelectric Multilayer Composites

TL;DR

This paper reports strong magnetoelectric effects in ferrite-PZT multilayers, highlighting the influence of material composition and interface quality on the magnitude of the effect, supported by theoretical analysis.

Contribution

It presents experimental measurements of magnetoelectric effects in various ferrite-PZT multilayers and introduces a theoretical model accounting for interface conditions to explain the results.

Findings

Nickel ferrite-PZT shows the strongest ME effect.

Zn substitution enhances ME coefficients due to better magneto-mechanical coupling.

Theoretical analysis aligns with experimental data, indicating strong interface coupling in nickel zinc ferrite-PZT.

Abstract

The observation of strong magnetoelectric effects is reported in thick film bilayers and multilayers of ferrite-lead titanate zirconate (PZT) and lanthanum nanganite-PZT. The ferrites used in our studies included pure and zinc substituted cobalt-, nickel- and lithium ferrites. Samples were prepared by sintering 10-40 mm thick films obtained by tape-casting. Measurements of ME voltage coefficients at 10-1000 Hz indicated a giant ME effect in nickel ferrite-PZT, but a relatively weak coupling in other ferrite-PZT and manganite-PZT systems. Multilayers prepared by hot pressing was found to show a higher ME coefficient than sintered samples. Evidence was found for enhancement in ME coefficients when Zn was substituted in ferrites. The Zn-assisted increase was attributed to low anisotropy and high permeability that resulted in favorable magneto-mechanical coupling in the composites. We analyzed the data in terms of our recent comprehensive theory that takes into account actual interface conditions by introducing an interface coupling parameter. Theoretical longitudinal and transverse ME voltage coefficients for unclamped and clamped samples are in general agreement with data. From the analysis we inferred excellent interface coupling for nickel zinc ferrite-PZT and weak coupling for other layered systems.