Abstract
We investigated in this paper a novel bilayer composite obtained by sol-gel and spin coating of the ferroelectric 0.92Na0.5Bi0.5TiO3–0.08BaTiO3 (abbreviated as BNT-BT0.08) and ferromagnetic CoFe2O4 phases, for miniature low-frequency magnetic sensors and piezoelectric sensors. This heterostructure, deposited on Si-Pt substrate (Si-Pt/CoFe2O4/BNT-BT0.08), was characterized using selected method such as: X-ray diffraction, dielectric spectroscopy, piezoelectric force microscopy, SQUID magnetometry, atomic force microscopy/magnetic force microscopy, and advanced methods of transmission electron microscopy. CoFe2O4/BNT-BT0.08 ferromagnetic–piezoelectric thin films show good magnetization, dielectric constant and piezoelectric response. The results of analyses and measurements reveal that this heterostructure can have applications in high-performance magnetoelectric devices at room temperature.
Highlights
In recent years, the manufacture of composite materials from components with different macroscopic properties was studied extensively[1,2,3,4,5]
We have investigated the composite thin film Si-Pt/CoFe2O4/BNT-BT0.08 in which BNT-BT0.08 and cobalt ferrite (CoFe2O4) films were deposited in two subsequent steps on Si-Pt buffer, by sol-gel and spin-coating techniques
It has been shown previously that the (1-x)BNT-xBT (BNT-BTx) solid solution has in the compositional domain x = 0.06–0.10 a nearly morphotropic phase boundary (MPB)[23,24] where rhombohedral Bi0.5Na0.5TiO3 and tetragonal BaTiO3 phases coexist
Summary
The magnetic hysteresis loops of Si-Pt/CoFe2O4/BNT-BT0.08 bilayer heterostructure (Fig. 5(a,b)) were recorded at 5 K and 295 K, under a magnetic field of ≤ 70 kOe, perpendicular to the BNT-BT0.08 layer plane. The magnetic parameters are higher for the CoFe2O4/BNT-BT0.08 composite thin film because the CoFe2O4 layer in this composite is thicker and has the crystallites larger than the CoFe2O4 layer in the BNT-BT0.08/CoFe2O4 composite structure[30] These results are in good agreement with ref.[31]. The measurements are carried out over a very small capacitance (CoFe2O4) in series with a high capacitance (BNT-BT0.08) which results in an equivalent capacitance smaller that of CoFe2O4 layer This explains the small dielectric constant of the heterostructure
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
