Colossal magnetoelectric response of PZT thick films on Ni substrates with a conductive LaNiO₃ electrode

We have characterized the magnetoelectric (ME) properties of Pb(ZrTi)O ₃/LaNiO₃/Ni (PZT/LNO/Ni) composites, which are fabricated using aerosol deposition. LNO acted as the bottom electrode for the PZT film and could effectively transfer the stress generated through the magnetostrictive effect of Ni into the piezoelectric PZT film. The PZT/LNO/Ni ME structure exhibits an ME coefficient α_E31 = 1 V cm^-1 Oe ^-1 at a very low bias magnetic field of 30 Oe and shows 8.5 V cm ^-1 Oe^-1 at a magneto-mechanical resonance frequency of 204 kHz corresponding to the Ni substrate. These huge ME coefficients are attributed to the improved coupling between the magnetostrictive Ni layer and the piezoelectric PZT thick film via the LNO layer, which is possible due to similar mechanical impedances of Ni, LNO and PZT.