Search

CuInP2S6 (CIPS) is a novel two-dimensional (2D) van der Waals (vdW) ferroelectric layered material with a Curie temperature of TC~315 K, making it promising for great potential applications in electronic and photoelectric devices. Herein, the ferroelectric and electric properties of CIPS at different thicknesses are carefully evaluated by scanning probe microscopy techniques. Some defects in some local regions due to Cu deficiency lead to a CuInP2S6–In4/3P2S6 (CIPS–IPS) paraelectric phase coexisting with the CIPS ferroelectric phase. An electrochemical strain microscopy (ESM) study reveals that the relaxation times corresponding to the Cu ions and the IPS ionospheres are not the same, with a significant difference in their response to DC voltage, related to the rectification effect of the ferroelectric tunnel junction (FTJ). The electric properties of the FTJ indicate Cu+ ion migration and propose that the current flow and device performance are dynamically controlled by an interfacial Schottky barrier. The addition of the ferroelectricity of CIPS opens up applications in memories and sensors, actuators, and even spin-orbit devices based on 2D vdW heterostructures. [ABSTRACT FROM AUTHOR]

Abstract: Although potassium niobate K4Nb6O17 single crystal is easy to absorb moisture due to the intercalation of water molecules in the crystal, single crystals can be grown in fiber shape using an original pulling down method. K4Nb6O17 single crystals are easy to break down in plate shape by cleavage which is in turn affected by moisture. The dielectric constant and electric polarization measurements show that K4Nb6O17 single crystal is with weak ferroelectricity. [Copyright &y& Elsevier]

In order to find high-performance multiferroic materials, which are good candidates for lead-free piezoelectric/ferroelectric films, a new type of heterostructural thin film of YMnO3/SnTiO3+ x (YST) was designed and produced. SnTiO3 is a metastable but promising lead-free ferroelectric material. Our expectation was that it could be stabilized by alternating YMnO3 layers. Here we report the fabrication and ferroelectric, piezoelectric and magnetic properties of YST films. Antiferromagnetic and ferroelectric properties were observed to coexist on the YST film with four layers, fabricated using the pulsed laser deposition method on (110) Nb:SrTiO3 substrates. Although some basic ferroelectric properties of the SnTiO3 films have previously been reported, further study is needed to obtain high-performance SnTiO3 films. [ABSTRACT FROM AUTHOR]

Samarium doped bismuth titanate thin films with the composition of Bi3.25Sm0.75Ti3O12 and with strong preferred orientations along the c axis and the (117) direction were fabricated on Pt/TiO2/SiO2/Si substrate by pulsed laser ablation. Measurements on Pt/BSmT/Pt capacitors showed that the c-axis oriented film had a small remanent polarization (2Pr) of 5 μC/cm2, while the highly (117) oriented film showed a 2Pr value of 54 μC/cm2 at an electrical field of 268 kV/cm and a coercive field Ec of 89 kV/cm. This is different from the sol-gel derived c-axis oriented Bi3.15Sm0.85Ti3O12 film showing a 2Pr value of 49 μC/cm2. [ABSTRACT FROM AUTHOR]

Multiferroic BiFeO3/Bi3.25Sm0.75Ti2.98V0.02O12 double-layered thin films on Pt/Ti/SiO2/Si were fabricated using the pulsed-laser deposition technique. The films showed greatly enhanced ferroelectric and ferromagnetic properties. The values of the remanent polarization (2Pr) and coercive field (Ec) were 71.8 μC/cm2 and 148 kV/cm at a maximum applied voltage of 13 V, respectively. The value of the magnetic moment was found to be 17.5 emu/cm3. The enhancement of the polarization originated from the BiFeO3 with Bi3.25Sm0.75Ti2.98V0.02O12 working as a barrier layer. The enhancement of the magnetization is from the structural distortion of BiFeO3, due to partial epitaxial growth on the bismuth titanate surface. [ABSTRACT FROM AUTHOR]

High quality BiFeO 3 film with enhanced remanent polarization and magnetization attracts much interest for its great application potential in information storage and photoelectric devices. Here we grew single-crystal epitaxial BiFeO 3 film on SrTiO 3 substrate through hydrothermal method at low temperature, the film has a quality higher than any reported BiFeO 3 films grown through hydrothermal method. Furthermore, BiFeO 3 film was grown through a 25 min rapid microwave-assisted hydrothermal process. The two BiFeO 3 films exhibited obvious light response to periodically switching on and off of a LED light, and the film grown through microwave-assisted hydrothermal method produced a 4.7V open-circuit voltage exceeding the band gap of BiFeO 3 originating from the ferroelectric photovoltaic effect. These results demonstrate that hydrothermal and microwave-assisted hydrothermal method are simple, inexpensive and rapid to grow high quality epitaxial BiFeO 3 film with potential application in photoelectric detection and photovoltaic. [ABSTRACT FROM AUTHOR]

0.5Ba(Ti 0.8 Zr 0.2 )O 3 -0.5(Ba 0.7 Ca 0.3 )TiO 3 (0.5BZT-0.5BCT), one of the most promising lead-free piezoelectric materials invented in recent years, has not been optimized for its thin film to show best electric performance. In this work, 0.5BZT-0.5BCT thin films were fabricated via a sol-gel technique, and the effects of solvent and additive on the microstructure, morphology and dielectric, ferroelectric, and piezoelectric properties were studied. Results showed that the 2-methoxyethanol (2-MOE) solvent resulted in 0.5BZT-0.5BCT thin films with much improved microstructure and morphology in comparison with thin film from absolute ethanol solvent. Furthermore, the film becomes even denser, smoother, and more homogeneous after the monomer ethylene glycol (EG) or polyethylene glycol of 400 molecular weights (PEG400) were added into the precursor with 2-MOE as solvent. Especially, addition of PEG400 into the solvent will result in the best thin film with both less macro and micro defects and high electric performance. The 0.5BZT-0.5BCT film from 2-MOE solvent with PEG400 additive shows a high dielectric constant ε up to 1756, dielectric tunability about 44%, P r around 17.2 μC/cm 2 , and E c about 39.0 kV/cm. [ABSTRACT FROM AUTHOR]