Synthesis of infinite-layer LaNiO2 films by metal-organic deposition

We report the synthesis of infinite-layer LaNiO2 thin films by metal organic decomposition. Our work is aimed to synthesize perovskite-like oxides with 3d9 electronic configuration, which is common to high-Tc copper oxides. The 3d9 configuration is very rare in oxides other than cuprates. Ni1+ oxides, even though Ni1+ is an unusual oxidation state, may be one of very few candidates. One example of the Ni1+ phases is infinite-layer LaNiO2. The bulk synthesis of LaNiO2 is difficult, but we demonstrate in this article that the thin-film synthesis of LaNiO2 by metal organic decomposition is rather easy. This is due to the advantage of thin films with a large-surface-to-volume ratio, which makes oxygen diffusion prompt. Resistivity measurements indicate that LaNiO2 is essentially a metal but unfortunately with no trace of superconductivity yet.Comment: 13 pages, 4 figure

Structural evolution and dopant occupancy preference of yttrium-doped potassium sodium niobate thin films

Sodium potassium niobate (KNN) is the most promising candidate for lead-free piezoelectric material, owing to its high Curie temperature and piezoelectric coefficients among the non-lead piezoelectric. Numerous studies have been carried out to enhance piezoelectric properties of KNN through composition design. This research studied the effects of yttrium concentrations and lattice site occupancy preference in KNN films. For this research, the yttrium-doped KNN thin films (mol% = 0, 0.1, 0.3, 0.5, 0.7 and 0.9) were fabricated using the sol-gel spin coating technique and had revealed the orthorhombic perovskite structures. Based on the replacement of Y3+ ions for K+/ Na+ ions, it was found that the films doped with 0.1 to 0.5 mol% of yttrium had less lattice strain, while films with more than 0.5 mol% of Y3+ ions had increased strain due to the tendency of Y3+ to occupy the B-site in the perovskite lattice. Furthermore, by analysing the vibrational attributes of octahedron bonding, the dopant occupancy at A-site and B-site lattices could be identified. O-Nb-O bonding was asymmetric and became distorted due to the B-site occupancy of yttrium dopants at high dopant concentrations of >0.5 mol%. Extra conduction electrons had resulted in better resistivity of 2.153× 106 Ω at 0.5 mol%, while higher resistivity was recorded for films prepared with higher concentration of more than 0.5 mol%. The introduction of Y3+ improved the grain distribution of KNN structure. Further investigations indicated that yttrium enhances the surface smoothness of the films. However, at high concentrations (0.9 mol%), the yttrium increases the roughness of the surface. Within the studied range of Y3+ , the film with 0.5 mol% Y3+ represented a relatively desirable improvement in dielectric loss, tan δ and quality factor, Qm

INFLUENCE OF WATER AND PRECURSOR MOLARITY ON THE TiO2 THIN FILMS DEPOSITED FROM SOLVENTLESS SOL-GEL

Titania (TiO2) of anatase, anatase-rutile and anatase-brookite-rutile thin films were successfully established from sol-gel dip coating technique using titanium tetraisopropoxide (TTIP) as precursors without the presence of solvent. The thin films were deposited on glass substrate and the type of TiO2 crystalline structure produced was depending upon the molar ratio of the TTIP and water. Results shown that the TTIP molarity is more substantial in determining the TiO2 thin films crystallinity and crystallite size as compared to the water molarity. Meanwhile, the desired phases and crystallite size can be controlled by manipulating the molar ratio of water and TTIP. Thus, the establishment of the desired phases (anatase mixed rutile), crystallinity and crystallite size (anatase: 15 nm, rutile: 30 nm) of TiO2 thin films from solvent less sol-gel can be controlled and encouraging to explore as an effort toward producing a sustainable green photocatalytic material

X-ray Absorption Studies of Ceria with Trivalent Dopants

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65899/1/j.1151-2916.1991.tb04328.x.pd

IDENTIFICATION OF SECOND PHASE DEPOSITED ON La-DOPED SrTiO3 PEROVSKITES SYNTHESIZED BY CITRIC-GEL METHOD

We examined deposition process of the second phase during sintering Sr0.7La0.3TiO3 perovskite at 1400°C and analyzed the detailed composition by means of SEM-EDX technique. The second phase deposited at the corners of the Sr0.7La0.3TiO3 matrix grains was confirmed to be Sr-doped rare-earth B-type La2O3

Schedule free pass in rod rolling

Translated from Japanese (R and D, Kobe Seiko Giho 1989 v. 39(1) p. 69-72)SIGLEAvailable from British Library Document Supply Centre- DSC:9022.06(BISI-Trans--27498)T / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Influence of yttrium dopant on the structure and electrical conductivity of potassium sodium niobate thin films

KNN thin films with diverse yttrium concentration (mol % = 0, 0.1, 0.3, 0.5, 0.7 and 0.9) were fabricated using sol-gel spin coating technique. Doped KNN revealed that Y3+ was successfully doped into the ABO3 perovskite lattice without changing the phase formation of KNN. The thickness of the deposited layer of KNN produced with increasing dopant concentration was determined to be 200 nm with dense and well-defined grains. Afterwards, the vibrational bonding and conductivity of KNN films with diverse yttrium concentration were identified according to the charge compensation mechanism. At high dopant concentration of > 0.5 mol %, O-Nb-O bonding was asymmetric and became distorted due to B-site occupancy by yttrium dopant. Further investigation revealed that charge compensation mechanism was shifted by increasing doping concentration. As a result, yttrium-doped KNN became semi-conductive at low yttrium concentration. Meanwhile, at high concentration, yttrium-doped KNN became an insulator and underwent ionic compensatio