Leakage current of multiferroic (Bi0.6Tb0.3La0.1)FeO3 thin films grown at various oxygen pressures by pulsed laser deposition and annealing effect

Abstract

Thin films of multiferroic (Bi0.6Tb0.3La0.1)FeO3 were grown on Pt∕Ti∕SiO2∕Si substrate under various oxygen pressures by pulsed laser deposition technique. X-ray diffraction patterns show that the crystallinity of the thin film is improved with decreasing depositing oxygen pressure and the thin film grown at a lower oxygen pressure of 0.01torr exhibits a single perovskite phase with preferred (001) orientation. Leakage current of the as-deposited thin films decreases with decreasing grown oxygen pressure. Significantly, the leakage current of the thin films can be reduced largely by an annealing process at 800°C with flowing oxygen. The annealed thin films show a relatively high resistivity and stable polarization loops with double remnant polarization of about 3μC∕cm2. The conduction properties of the thin films have been well analyzed, and it is indicated that the dominant conduction mechanism is the space-charge-limited conduction for the thin film grown at higher oxygen pressure and the Poole-Frenkel conduction for the thin films grown at lower oxygen pressure.

Self-assembled Nanocomposite Oxide Films: Design, Fabrication, and Properties

“…The NRBS results clearly show that there are V O s in BFO films: 11.2% deficient in the asdeposited film and 6.0% deficient in post-annealed film compared to the ideal case. At the same time, the V O s can be effectively reduced by the post-annealing which is consistent with reported results (Wang et al, 2006). Furthermore, the leakage current densities of asdeposited and annealed BFO and BFO:SmO films were measured and shown as Fig.…”

“…Ferroelectric materials with lower leakage current typically exhibited smaller dielectric loss (Joshi, et al, 2000). For example, Wang et al reported that reduction of oxygen vacancies in doped BFO films reduced the leakage current and then the dielectric loss (Wang et al, 2006). Figure 9 shows the leakage current density vs. electric field (J-E) characteristics of BFO:SmO, BFO, and SmO thin films.…”

“…It has been widely reported that oxygen vacancies (V O s), rather than Fe 2+ ions, are the main cause of high leakage current densities in BFO thin films. Efforts have been made to reduce the V O s by introducing post-annealing in an oxygen atmosphere, doping with higher valence ions, and oxygen ion implanting (Wang, et al, 2006). To investigate the oxygen vacancies effect on the leakage current density in the present study, some pure BFO films and BFO:SmO nanocomposites were subjected to an in situ annealing in oxygen (~500 Torr) at a temperature of 390 o C for 60 mins.…”

Structural, magnetic and dielectric properties of nano-crystalline Ni-doped BiFeO3 ceramics formulated by self-propagating high-temperature synthesis

“…To overcome this problem, various approaches have been proposed, such as reduction in oxygen vacancies, domination of the ohmic conduction, and intergrain depletion in grain boundary limited conduction. The efforts have been made to reduce the leakage current density by either introducing dopants or using different fabrication methods [12][13][14][15][16]. At present, many researchers are engaged in the enrichment of multiferroic properties of BiFeO 3 -relevant materials, using different trivalent dopants such as La [17], Mn [18], Sm [19] and Ti [20].…”

Magnetodielectric coupling in epitaxial Nd2CoMnO6 thin films with double perovskite structure

“…The ferroelectric loop of NCMO thin film could not be measured due to leakage current characteristics and it could be due to the existence of Mn 2þ and oxygen vacancies. 13 The magnetodielectric constant is defined as de MD ½eðHÞ À eð0Þ =eð0Þ, where e(H) and e(0) are the dielectric constants (e) under applied field and zero applied magnetic fields. The temperature dependence of de MD for 0.1 kOe and 0.5 kOe magnetic fields is shown in Fig.…”