Low Dielectric Loss and Multiferroic Properties in Ferroelectric/Mutiferroic/Ferroelectric Sandwich Structured Thin Films

Abstract

Bismuth ferrite (BiFeO 3 ) has proven to be promising for a wide variety of microelectric and magnetoelectric devices applications. In this work, a dense (Ba 0.65 Sr 0.35 )TiO 3 (BST)/ (Bi 0.875 Nd 0.125 )FeO 3 (BNF)/BST trilayered thin film grown on Pt-coated Si (100) substrates was developed by the rf-sputtering. For comparison, single-layered BNF and BST were also prepared on the same substrates, respectively. The results show that the dielectric loses suppression in BST/BNF/BST trilayered thin films at room temperature but has enhanced ferromagnetic and ferroelectric properties. The remnant polarization (P r ) and coercive electronic field (E c ) were 5.51 µC/cm 2 and 18.3 kV/cm, and the remnant magnetization (M r ) and coercive magnetic field (H c ) were 10.1 emu/cm 3 and 351 Oe, respectively, for the trilayered film. We considered that the bismuth's volatilization was limited by BST bottom layers making the Bi/Fe in good station, and the action of BST layer in the charge transfer between BNF thin film and electrode led to the quite low leakage current and enhanced multiferroic property. The origin of the mechanism of the highly enhanced dielectric constant and decreased loss tanδ was discussed.Coatings 2019, 9, 502 2 of 8 fields [21,22]. The electric field control of magnetism requires deterministic control of the magnetic order, and the magnetoelectric coupling in multiferrous BiFeO 3 can be understood [23]. In addition, the others FE/MF heterostructured thin films and FE/MF(FE)/FE trilayered structural thin films were prepared [24][25][26][27], but these films still have a high leakage current density and a dissipation factor.In this work, Ba 0.65 Sr 0.35 TiO 3 , Bi 0.875 Nd 0.125 FeO 3 and Ba 0.65 Sr 0.35 TiO 3 -Bi 0.875 Nd 0.125 FeO 3 -Ba 0.65 Sr 0.35 TiO 3 thin films grown on Pt/Ti/SiO 2 /Si (100) substrates were prepared by radio frequency magnetron sputtering. The ferroelectric, ferromagnetic, and electrical properties of these film samples were investigated. The low dielectric loss, low leakage current density, and multiferroic properties enhancement mechanism of the sandwich structural thin films are also discussed.

High-Tc Fe-based ferroelectric compound with large spontaneous polarization and narrow bandgap

“…1b and c, we also measured the dielectric anomaly and dielectric loss during heating and cooling at six frequencies (5 KHz, 10 KHz, 100 KHz, and 1 MHz), indicating that the dielectric constant of compound 1 gradually increases with the decrease of frequency, showing a certain dependence. 35,36 It can also be seen that the dielectric loss of compound 1 is relatively small. In addition to dielectric measurement, differential scanning calorimetry (DSC) is also one of the effective methods to determine the phase transition characteristics.…”

Functional Ferroic Materials, Films and Devices

“…Similarly, Hu et al prepared multilayer BiFeO 3 /BaTiO 3 samples and systemically studied their magneto-electric effect. With the increase in the magnetic field from 0 to 1200 Oe, the Pr of pure 100 nm BFO films was almost stable, but that of multilayer BiFeO 3 /BaTiO 3 samples increased from 66 µC/cm 2 to 97 µC/cm 2 due to the interfacial effects and multiferroic coupling [16].…”