Polarization and leakage current properties of self-supported bismuth sodium titanate ceramic films deposited by aerosol deposition method

Abstract

Self-supported (Bi 0.5 Na 0.5 )TiO 3 (BNT) dense ceramic films with a thickness of approximately 20¯m have been fabricated by use of an aerosol deposition method with heat treatment and sapphire single crystal substrates. Investigations of their constitution phase and crystal structure, observation of their microstructure, and measurement of polarization properties and leakage current density (J ) were performed. Wlile the films heat-treated at 800 and 900°C in air indicated the low J µ 10 ¹7 A/cm 2 at 150 kV/cm, the sintered bulks and the films annealed at 900°C in the BNT starting raw powder showed the relatively high J of approximately 10 ¹6 A/cm 2 at 150 kV/cm. These films heat-treated at 800 and 1000°C in air and sintered bulks showed the almost the same coercive field (E c ) of approximately 57 kV/cm (in the 56 to 58 kV/cm range), and the films heat-treated at 1000°C in air exhibited good polarization properties and remanent polarization (P r ) of 25¯C/cm 2 . The AD method is proposed to be effective for obtaining self-supported BNT thick films with good saturated hysteresis loops and low J.

Elaboration of lead-free Na 0.5 Bi 0.5 TiO 3 –BaTiO 3 (NBT-BT) thick films by aerosol deposition method (ADM)

“…This corresponds well to the grain size effect observed for ferroelectric ceramics materials; For example, BaTiO 3 ceramics with grain size lower than around 100 nm are not ferroelectrics, because grain size is too small to allow for the occurrence of ferroelectric ordering and so the structure is no more tetragonal but becomes cubic [39][40][41]. This behavior also corresponds well to previous results obtained by ADM: ferroelectric behavior was only obtained after thermal annealing of the films [13,30,31,[34][35][36].…”

“…For KNN, thick films were successfully obtained on Pt/Sapphire substrates [34]. As for PZT, the ferroelectric properties were obtained only after annealing at 700°C for 1 h. NBT films were deposited on Pt/Ti/Al 2 O 3 and sapphire substrates by the Akedo's group for which ferroelectric properties were again obtained only after annealing at 1000°C for 1 h [35,36].…”

Effect of starting powder morphology on film texture for bismuth layer-structured ferroelectrics prepared by aerosol deposition method

“…The aerosol deposition (AD) method based on roomtemperature impact consolidation (RTIC) phenomena attracts attention because it can form thick ceramic layers of simple or complex compositions at room temperature. [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] The use of this method has already been reported for the fabrication of Pb(Zr,Ti)O 3 (PZT) [22][23][24][25] and its application as a component in a piezoelectric actuator. 26) Also, this method was successfully used to enhance the dielectric properties of PbTiO 3 and (Pb 0.91 ,La 0.09 )(Zr 0.65 ,Ti 0.35 )O 3 (PLZT) in the THz range, 27) and the electro-optical properties of PLZT films.…”

“…30) For optical MEMS scanning devices without using Si, a wide optical scan angle at a high resonance frequency (applied voltage of less than 30 V) was achieved by using BTO thick films deposited on Pt=Ti=yttriumstabilized zirconia (YSZ) substrates with a high electric field applied to the BTO layer. 31,32) We obtained enhanced polarization properties for Bi based perovskite oxide ceramic films [SrBi 2 Ta 2 O 9 (SBTa) 33) and (Bi 0.5 Na 0.5 )TiO 3 (BNT) 34,35) where high quality single crystal growth was achieved 36,37) ] by using the AD method because of suppressed Bi vaporization due to low temperature treatment.…”

Synchrotron radiation X-ray diffraction evidence for nature of chemical bonds in Bi4Ti3O12ceramic powders and grain-orientation mechanism of their films formed by aerosol deposition method

“…BTO films deposited by the AD method 20) have a higher permittivity than those deposited by conventional methods. 21) It is reported that dielectric properties of PbTiO 3 films, 22) dielectric and electro-optical properties of (Pb0 .91 ,La 0.09 )(Zr 0.65 ,Ti 0.35 )O 3 films 22,23) and polarization of (Bi 0.5 ,Na 0.5 )TiO 3 films 24,25) are enhanced by the AD method. Oriented films have been also deposited by the AD method.…”