Enhanced Ferroelectric, Dielectric Properties of Fe-Doped PMN-PT Thin Films

Fe-doped 0.71Pb(Mg1/3Nb2/3)O3-0.29PbTiO3 (PMN-PT) thin films were grown in Pt/Ti/SiO2/Si substrate by a chemical solution deposition method. Effects of the annealing temperature and doping concentration on the crystallinity, microstructure, ferroelectric and dielectric properties of thin film were investigated. High (111) preferred orientation and density columnar structure were achieved in the 2% Fe-doped PMN-PT thin film annealed at 650 °C. The preferred orientation was transferred to a random orientation as the doping concentration increased. A 2% Fe-doped PMN-PT thin film showed the effectively reduced leakage current density, which was due to the fact that the oxygen vacancies were effectively restricted and a transition of Ti4+ to Ti3+ was prevented. The optimal ferroelectric properties of 2% Fe-doped PMN-PT thin film annealed at 650 °C were identified with slim polarization-applied field loops, high saturation polarization (Ps = 78.8 µC/cm2), remanent polarization (Pr = 23.1 µC/cm2) and low coercive voltage (Ec = 100 kV/cm). Moreover, the 2% Fe-doped PMN-PT thin film annealed at 650 °C showed an excellent dielectric performance with a high dielectric constant (εr ~1300 at 1 kHz).

Morphological and Structural Evolution of Chemically Deposited Epitaxially LaNiO3 Thin Films

We report the preparation and characterization of epitaxial LaNiO3 (LNO) thin films by chemical solution deposition method using lanthanum and nickel acetylacetonates as starting reagents dissolved in propionic acid. In order to obtain further information regarding the decomposition behavior of the film, the precursor solution was dried to obtain the precursor powder, which was investigated by thermal analyses and X-ray diffraction measurements (XRD). The LNO perovskite thin films were deposited by spin coating on SrTiO3(100) single crystal substrates. A detailed study with different crystallization temperatures (600–900 °C) at two different heating ramps (5 and 10 °C/min) was performed. Oriented LaNiO3 thin films with good out-of-plane textures were obtained with optimal surface morphologies.

Effect of pH of coating solution on the adhesion strength and corrosion resistance of hydroxyapatite and octacalcium phosphate coated WE43 alloy

Hydroxyapatite (HAp) and octacalcium phosphate (OCP) layers were formed on Mg- 4mass% Y- 3mass% rare earth (WE43) alloy by a chemical solution deposition method at various pH values of pH 5.5, 6.2, 7.5, and 8.6. Adhesion strength of HAp and OCP layers was evaluated before and after immersing in a medium for 14 days by a pull-off test. The corrosion resistance of these coatings was measured by polarization tests performed in a simulated body fluid (SBF). XRD analysis demonstrated that HAp coating layers were formed at pH 7.5 and 8.6, while OCP coating layers were formed at pH 5.5 and 6.2. Adhesion test results showed that the as-coated pH7.5-HAp layer had the highest adhesion strength of 8.6 MPa, which was attributed to the very dense structure of the coating layer. The as-coated pH8.6-HAp layer showed the adhesion strength of 6.5 MPa. The adhesion strength of the as-coated pH5.5- and pH6.2-OCP layers was 3.9 and 7.1 MPa, respectively, that was governed by the thick and fragile property of the layers. After immersing in the medium for 14 days, the adhesion strength of pH7.5- and pH8.6-specimens decreased to 5.8 and 5.6 MPa, respectively. The pitting corrosion and formation of Mg(OH)2 under the HAp layers were responsible for the decrease of adhesion strength. The polarization tests in SBF at 37 °C showed that the corrosion current density decreased with the HAp and OCP coatings, indicating the improvement of the corrosion resistance of WE43 alloy. The HAp coatings improved the corrosion resistance more efficiently than the OCP coatings.

Study of Mn–Co–Ni–O thin films incorporated with Cu and Cu/Sc elements and properties of the detectors

Thin films [Formula: see text] (MCNO), [Formula: see text] (MCNCuO) and [Formula: see text] (MCNCuScO) are prepared by Chemical Solution Deposition method. The results show that the addition of Cu and Cu/Sc elements can reduce the grain boundary energy and the grain boundary angle to improve the single crystal degree of MCNO thin film. Through the analysis of MCNCuScO thin film, it is found that the stability of spinel structure mainly depends on the octahedron rather than tetrahedron. The bandgap of the samples from small to large is separately MCNCuScO, MCNCuO and MCNO films. The absorptivity within the waveband of [Formula: see text] plays a decisive role in the performance of the detector. At the same frequency, the MCNCuO thin film detector has the highest voltage responsivity, followed by the MCNCuScO thin film detector, while the MCNO film detector has the lowest responsivity.

Large magnetodielectric response of PST/LSMO/LCMO film over a wide temperature range

Pb0.6Sr0.4TiO3/La0.7Sr0.3MnO3/La0.7Ca0.3MnO3 (PST/LSMO/LCMO) film is grown on Si substrate by chemical solution deposition method.

Effect of pH of Coating Solution on Adhesion Strength of Hydroxyapatite and Octacalcium Phosphate Coatings on AZ31 Magnesium Alloy

Hydroxyapatite (HAp) and octacalcium phosphate (OCP) coatings were formed on a Mg-3Al-Zn (AZ31) alloy with a chemical solution deposition method using a Ca-EDTA solution at various pH levels. The adhesion strength of the coatings was examined using the pull-off method. The microstructures of HAp and OCP coatings were measured X-ray diffraction (XRD). The morphology and composition of the surface and cross section of the samples before and after the adhesion test were characterized using scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS), and a 3D profilometer. The results showed that plate-like OCP crystals grew from a continuous OCP layer on the surface of the AZ31 substrate in the case of a pH 6.3 coating solution. At pH values of 7.5 and 8.6, the HAp coating showed a two-layer structure with a HAp rod-like outer layer and a HAp continuous inner layer. Regardless of the pH of the coating solutions, a very thin Mg (OH)2 intermediate layer was formed between OCP or HAp coating and substrate. The highest adhesion strength of the coatings was 6.7±0.5 MPa, achieved at a coating solution pH value of 7.5. A part of Mg (OH)2 layer remained on the substrate, indicating that the delamination occurred in the Mg (OH)2 intermediate layer. The primary particles in the inner layer formed at pH 7.5 was smaller than those at pH 8.6. This result indicates that the initial corrosion of substrate AZ31 at pH 7.5 was more rapidly than that at pH 8.6, presumably leading to the formation of mixed layer of Mg (OH)2 and calcium phosphate. Further investigation is necessary to understand the better adhesion strength at pH 7.5 than that at pH 8.6. This good adhesion could be due to the flawless and rod-like uniform crystal, which had the densest and finest structure on the surface.