Different Iron Doping Levels The Bati <sub> 1-z </ Sub> Fe <sub> Z-</ Sub> The O <sub> 3 </ Sub> And Of Tb <sub> 1-x </ Sub> Dy < Sub> X </ Sub> Fe <sub> 2-y </ Sub> Layered Composite

In this paper we discussed the magnetoelectric (ME) effect in bilayers of Fe-doped BaTiO₃ with the doping level ranging from 0.01 to 0.02 and commercial Tb_1-xDy_xFe_2-y Fe-doped BaTiO₃ has been synthesized with sol-gel technique. The resultant powder was pressed into rods of 10 mm in diameter and 15 mm in length, and treated at 10 MPa and 900℃for 10h with a hot-pressing facility, then further sintered at 1300℃for 10h, at last the pressed rods were cut into pellets with 1mm in thick. The patterns of XRD revealed the absence of any impurities except tetragonal structure (with point group 4mm) of Re-doped BaTiO₃. Their transformation point of ferroelectric to paraelectric and the corresponding latent heat of phase transformation were observed to decrease with increasing the doping level of Fe³⁺ by the test of differential scanning calorimetry (DSC). These results suggest that the doping increases the disorder in structure and in the distribution of electric dipoles in the perovskite. Bonded bilayers Fe-doped BaTiO₃ and Tb_1-xDy_xFe_2-y have been fabricated and their magnetoelectric effect has been investigated. We found that when the doped-level is above 1%, the ME curves for bilayer Fe-BaTiO₃/Tb_1-xDy_xFe_2-yare quite different from that of 1% ones, they are saturated curves. The sample containing a layer of BaTi_0.985Fe_0.015O₃ was found to show a maximum transverse ME coupling in these bilayer composites, about 1420 mV Oe^-1mV^-1. Analysis shows that the doped BaTiO₃ with doping level at about 1.5% should be a largest piezoelectric coefficient in these perovskites...