Ferroelectric properties of polycrystalline bismuth titanate films by Nd3+/W6+ cosubstitution

Abstract

Articles you may be interested inStructural, electrical, and magnetic properties of chemical solution deposited Bi ( Fe 0.95 Cr 0.05 ) O 3 thin films on platinized silicon substrates Structural, ferroelectric, dielectric, and magnetic properties of BiFeO 3 / Bi 3.15 Nd 0.85 Ti 3 O 12 multilayer films derived by chemical solution deposition

Synthesis and Characterization of Bismuth Titanate by an Aqueous Sol–Gel Method

“…The Raman mode D at B830 cm À1 can be assigned as A 1g mode, and it is representative of the symmetric Ti-O stretching vibration; the B530 cm À1 (peak C) and B250 cm À1 (peak B) modes can be assigned as B 2g 1B 3g modes originating from the lifting of E g degeneracy, they are ascribed to the opposing excursions of the external apical oxygen atoms of the TiO 6 octahedron and the torsional bending of TiO 6 octahedra, respectively. 5, 23,24 The peak A at B90 cm À1 is due to Bi-O stretching vibration. 23,25 The mode E at B740 cm À1 is typical of pyrochlore phase.…”

Strong Upconversion Photoluminescence and Large Ferroelectric Polarization in Er3+–Yb3+–W6+ Triply Substituted Bismuth Titanate Thin Films Prepared by Chemical Solution Deposition

“…Therefore, Er 3+ –Yb 3+ –W 6+ cosubstitution significantly improved the ferroelectricity of the thin films. It has been reported that W 6+ ion substitution of B ‐site (Ti 4+ ions) can also effectively improve ferroelectric properties of other thin films such as (La 3+ , Nd 3+ , and Pr 3+ )‐doped BiT thin films, Pb(Zr,Ti)O 3 thin films, CaBi 4 Ti 4 O 15 thin films, and SrBi 2 Ta 2 O 9 thin films 15–17 . In BiT‐based thin films, A ‐site substitution of larger Bi 3+ ions by smaller rare‐earth ions in the pseudo‐perovskite layer can result in largely enhanced rotation of TiO 6 octahedra in the a – b plane and a shift of the octahedron along a axis, 27–29 whereas B ‐site substitution of larger Ti 4+ ions by highly valent W 6+ ions can decrease oxygen vacancies to reduce domain pinning, 25,26 and make the polar ions move more easily.…”

“…The defects usually act as traps to induce nonradiative transitions, and then results in emission degradation. [22][23][24] The high-valent W 61 substitution with proper concentration can decrease concentration of the oxygen vacancies in the host lattices, 25,26 [15][16][17] In BiT-based thin films, A-site substitution of larger Bi 31 ions by smaller rare-earth ions in the pseudo-perovskite layer can result in largely enhanced rotation…”

“…Our previous study indicated that Er/Yb codoped bismuth titanate thin films showed good upconversion photoluminescent properties while excited at 980 nm, but their ferroelectric properties such as remnant polarization values were still unsatisfactory 14 . It has been reported that B ‐site (Ti 4+ ions) substitution by high‐valent W 6+ ions can effectively improve ferroelectric properties of bismuth titanate [Bi 4 Ti 3 O 12 (BiT)]‐based thin films 15–17 . This motivated us to study A ‐site (Er 3+ and Yb 3+ ions) and B ‐site (W 6+ ions) cosubstituted bismuth titanate thin films with an aim to achieve combination of strong upconversion emission with good ferroelectric properties.…”

Microstructures and electrical properties of Nd3+/V5+-cosubstituted Bi4Ti3O12 thin films

“…In another case, it is found that B-site substitution in BiT by some ions with higher charge valences such as V 5+ , Nb 5+ and W 6+ could effectively improve the ferroelectric properties by decreasing the space charge density of BiT thin films [4][5][6]. Recently, A-and B-sites cosubstitution in BiT films has also been reported to be more effective in improving ferroelectric properties and fatigue endurance [7][8][9][10][11]. For example, Uchida et al [11] have reported that the Nd 3+ /V 5+ -cosubstituted BiT thin films exhibit ferroelectric properties superior to those of Nd 3+ -substituted BiT.…”