Dielectric, piezoelectric and magnetic behavior of CoFe2O4/BNT-BT0.08 monolayer thin films composites

We report in this paper on the monolayer composites thin films that have the magnetic spinel CoFe2O4 and thepiezoelectric perovskite BNT-BT0.08 as constituent phases. Composite thin films of CoFe2O4 and BNT-BT0.08, withmolar ratios of 0.5:1, 1:1 and 1.5:1, have been deposited by spin coating method from a sol precursor, mixturetype, of CoFe2O4 and BNT-BT0.08. The monolayer thin films, deposited on Si/SiO2/TiO2/Pt substrate, werecharacterized using selected methods, such as: X-ray diffraction, scanning electron microscopy, atomic forcemicroscopy/piezoelectric force microscopy, dielectric spectroscopy, and vibrating sample magnetometer. X-raydiffraction demonstrated the two phases: cubic CoFe2O4 and rhombohedral BNT-BT0.08. Furthermore, the Si/SiO2/TiO2/Pt/BNT-BT0.08/CoFe2O4 monolayers show a simultaneous enhancement of both the magnetizationand coercivity with the increase of the magnetic phase, accompanied by a decrease of the dielectric constant. Theobtained results reveal that the investigated monolayer structures present superior properties compared to thoseof bilayer composites