Multiferroic and magnetoelectric properties of MnFe2O4/(Pb0.8Sr0.2)TiO3 composite films

Abstract

MnFe2O4/(Pb0.8Sr0.2)TiO3 (MFO/PST20) heterostructured composite films with three different structures have been grown on Pt/TiO2/SiO2/Si substrates by metal–organic decomposition processing via spin coating technique. The structural analysis revealed that the crystal axes of the MnFe2O4 are aligned with those of the PST20 ferroelectric matrix with obvious interfaces and no diffusions exist in all the three composite films. These composite films exhibit simultaneously multiferroic and magnetoelectric responses at room temperature. The growth structure of MFO and PST20 layers has an effect on multiferroic and magnetoelectric coupling behaviours of the composite films. The bi- and four-layered MFO/PST20 composite films exhibit superior ferroelectric properties compared to the tri-layered film. The increasing MFO and PST20 layers in the composite films enhance ferromagnetic properties and are closely related to the strain release in MnFe2O4 phase. The MFO/PST20 bi-layered composite film shows a high magnetoelectric voltage co-efficient αE ~ 194 mVcm−1Oe−1 at a dc magnetic field Hdc ~ 2.5 kOe. A significant decrease in αE value has been observed for tri- and four- layered composite films. A close correlation between phase selective residual stress and magnetoelectric properties has been emerged. The results are reasonably encouraging for employing MnFe2O4 for growing multiferroic–magnetoelectric composite films.