Fabrication of the preferentially orientated LiNbO3 nanoparticles and their ferroelectric behaviors

Preferentially orientated E-beam TiN thin films using focused jet of nitrogen gas

A modified electron beam evaporator has been used judiciously to synthesize TiN thin films with (111) preferred orientation. This new design involved in creating local plasma by accelerating the secondary electrons emitted from the evaporating ingot by a positively biased semi-cylindrical anode plate kept in the vicinity and a jet of N2 gas has been focused towards the substrate as a reactive gas. We have observed a preferred orientation (111) with 25 degree angle to the surface normal and this was confirmed by pole figure analysis. The phenomenon of preferred orientation (111) has been explai…

Highly (111)-orientated BiFeO3 thin film deposited on La0.67Sr0.33MnO3 buffered Pt/TiO2/SiO2/Si (100) substrate

Multiferroic BiFeO3 (BFO) thin film exhibiting desired ferroelectric and enhanced magnetic properties was grown on La0.67Sr0.33MnO3 (LSMO) buffered Pt/TiO2/SiO2/Si substrates by off-axis RF magnetic sputtering, where a highly (111)-oriented texture was obtained. The BFO/LSMO thin film exhibits excellent ferroelectric and dielectric behaviors (2Pr ~210.7 μC/cm2, 2Ec~435 kV/cm, εr ~116.8, and tanδ ~ 2.7% at 1 kHz), together with a long fatigue endurance up to 1010 switching cycles at amplitude of 300 kV/cm. An enhancement in magnetic behavior was also observed with Ms=89.5 emu/cm3, which is larg…

Effect of photons on atoms in crystallization of amorphous silicon films

The preferentially (220) orientated polycrystalline silicon films have been fabricated by performing photon-involved rapid thermal annealing upon amorphous silicon films. In contrast, conventional thermal annealing of the silicon amorphous films results in the preference of (111) orientated crystallization. This difference reveals the overlooked impaction of photons upon silicon atoms, which results in the preferential orientation of lattice plans with the smallest density of atoms on their projection plane rather than the lowest energies.

Orientation-dependent ferroelectricity of strained PbTiO$_3$ films

PbTiO$_3$ is a simple but very important ferroelectric oxide that has been extensively studied and widely used in various technological applications. However, most previous studies and applications were based on the bulk material or the conventional [$001$]-orientated films. There are few studies on PbTiO$_3$ films grown along other crystalline axes. In this study, a first-principles calculation was performed to compute the polarization of PbTiO$_3$ films strained by SrTiO$_3$ and LaAlO$_3$ substrates. Our results show that the polarization of PbTiO$_3$ films strongly depends on the growth ori…

受限氧空位迁移驱动铁电开关

Confined Oxygen-Vacancy Migration Drives Ferroelectric Switching

本研究通过第一性原理计算发现，Bi2SeO5中的氧空位在SeO3单元内受限迁移，产生可开关的极化，解释了其反常铁电性。