Influence of doping and doping level on magnetoelectric coupling in layered composites Tb1-xDyxFe2-y/Ba-Ti1-zMzO3+δ (M = Fe, Cr, Mn, Co)

Perovskites BaTi1-zMzO3+delta (M = Fe, Cr, Mn, Co) has been sol-gel synthesized. Their transformation point of ferroelectric to paraelectric and the latent heat of the transformation were found a little lower than those for pure BaTiO3 (BTO), respectively. Layered composites Tb1-xDyxFe2-y-BaTi(1-z)MzO(3+delta) have been fabricated. Their magnetoelectric (ME) effect has been investigated. All the bilayers containing the doped BTO displayed a stronger ME effects than that containing pure BTO does. The bilayer Tb1-xDyxFe2-y-BaTi0.99Cr0.01O3+delta was observed to show a larger ME coupling in the composites containing other doped BTO. While Tb1-xDyxFe2-y-BaTi0.985Fe0.015O3+delta showed the largest ME effects in the bilayers Tb1-xDyxFe2-y-BaTi1-zFezO3+delta (0 <= z <= 0.02). Additionally, the ME voltage coefficient for the trilayers Tb1-xDyxFe2-y-BaTi0.99M0.01O3+delta-Tb1-xDyxFe2-y was observed to be two or three times larger than that observed in the bilayers composed by the same substances. Theoretical analyses have been given for these observations. All the results suggest that the doped BTO can be a new choice of piezoelectrics in fabricating layered ME composites.