Permanganate (rare Earth Alloy) - Magnetoelectric Effect In Lead Zirconate Titanate Ferroelectric Ferromagnetic Multilayer

Perovskite-type La_0.7Sr_0.3MnO₃ (LSMO) powder samples were synthesized by the sol-gel method. The powder was pressed into pellets and treated with a hot-press facility. The hot-pressed samples were further sintered at 1573K to obtain dense LSMO samples with better magnetic parameters. PZT was first poled by heating to 425K and cooling back to room temperature in an electric field of 30～50kV/cm perpendicular to the sample plane. Then both planes of PZT were painted by silver electrode. LSMO-PZT bilayers were bonded by slow-dry epoxy resin with hardener.The structure of LSMO samples was represented by x-ray diffraction(XRD). The morphology was observed through scanning electronic microscopy(SEM). It was found that the stacking density of hot pressed LSMO was larger than that of the not hot pressed one. The magnetization was measured by a vibrating sample magnetometer. The bilayers exhibited superior ME coupling compared to thick-film composites prepared by tape casting process. The transverse coupling is stronger than the longitudinal interactions and a maximum in the ME voltage coefficient was measured at H=150Oe. The voltage coefficients were then measured as the frequency f of the ac fieldδH was varied. Upon increasing fα_E.31 increased gradually with minor peaks at 80kHz and 170kHz, and received a maximum of 1300mV/cm Oe at 268kHz. There is excellent agreement between theory and the ME data measurement.In order to adapt to the requirement of the practical application , on the basis of results of previous work, we simplified the experimental equipment , improved the sensitivity of the sample, and did further research of the ME effect in laminate composites of Tb_1-xDy_xFe_2-y-Pb(Zr, Ti)O₃ (TDF-PZT)driven by single magnetic field. The PZT powder made by chemical method was pressed into disks of 10mm in diameter and lmm in thickness. The disks then were sintered at different temperatures from 1000°C to 1200°C to obtain PZT samples in different compactness (or piling density). The laminates were bonded with slow-dry epoxy. For stabilizing the electric charge at both ends of the PZT, we parallel connected a suitable capacitance with the samples and made both in a small case and insulated from the ambience. The ME voltage was measured as a function of the applied field H. a strong ME coupling has been observed in the laminates by a technique of single magnetic field driven magnetoelectric coupling. The results obtained are far from that observed in two-field driven ME effect for the same material. This technique can be expected to simplify the applications of ME effect in some fields.