Correlation of magnetoelectric and delta-E effects in ferromagnetic-piezoelectric layered composites

Magnetoelectric (ME) coupling and its dependence on delta-$E$-effect have been studied in trilayers of ferromagnetic metals and lead zirconate titanate (PZT). Measurements on samples with PZT and Fe, Co, Ni or permendur (an alloy of Co-Fe-V) show evidence for strong ME interactions. Our theoretical model for bias magnetic field H dependence of ME effect predicts contributions due to two mechanisms: variation of piezomagnetic and compliance coefficients with H. The individual contributions from the two sources can be measured in the electromechanical resonance (EMR) region for the composite. Data on frequency dependence of ${\rm M}{\rm E}$ coefficient reveal a giant coupling at electromechanical resonance (EMR), at 200-300 kHz for radial modes and at $\sim $2.7 MHz for thickness modes. Variation of compliance coefficients with H (delta-E-effect) results in a frequency shift of peak ME voltage coefficient. Theoretical profiles of ${\rm M}{\rm E}$ coefficient vs. frequency agree with the data. These results are of importance for the design of signal processing devices that requires fine tuning. 1. M. I. Bichurin, D.A. Filippov, V. M. Petrov, V. M. Laletin, N. Paddubnaya, and G. Srinivasan, Phys. Rev. B \textbf{68}, 132408 (2003). - supported by grants from the Russian Ministry of Education (Å02-3.4-278), the Universities of Russia Foundation (UNR 01.01.026) and the National Science Foundation (DMR-0302254).