The local structure of several samples of BaTiO3 prepared by solution-gelation method with different particle sizes has been investigated using XAFS. Although the macroscopic crystal structure changes from tetragonal to cubic at room temperature when the particle size is smaller than 100 nm, Raman and XAFS spectroscopy measurements obtain that Ti atoms are displaced from the center of cubic sym...

The crystal structure of bulk SrTiO3(STO) transitions from cubic to tetragonal at around 105 K. Recent local scanning probe measurements of LaAlO3/SrTiO3 (LAO/STO) interfaces indicated the existence of spatially inhomogeneous electrical current paths and electrostatic potential associated with the structural domain formation in the tetragonal phase of STO. Here we report a study of temperature ...

The effect of growth temperature on the atomic layer deposition of zirconium oxide (ZrO₂) dielectric thin films that were fabricated using a CpZr[N(CH₃)₂]₃/C₇H₈ cocktail precursor with ozone was investigated. The chemical, structural, and electrical properties of ZrO₂ films grown at temperatures from 250 to 350 °C were characterized. Stoichiometric ZrO₂ films formed at 250-350 °C with an atomic...

Silver azide (AgN3) was compressed up to 51.3 GPa. The results reveal a reversible second-order orthorhombic-to-tetragonal phase transformation starting from ambient pressure and completing at 2.7 GPa. The phase transition is accompanied by a proximity of cell parameters a and b, a 3 rotation of azide anions, and a change of coordination number from 4-4 (four short, four long) to eight fold. Th...

A wardite mineral sample from Lavra Da Ilha, Minas Gerais, Brazil has been examined by vibrational spectroscopy. The mineral is unusual in that it belongs to a unique symmetry class, namely the tetragonal-trapezohedral group. The structure of wardite contains layers of corner-linked -OH bridged MO6 octahedra stacked along the tetragonal C-axis in a four-layer sequence and linked by PO4 groups. ...

The compounds UCuOP and NpCuOP have been synthesized and their crystal structures were determined from low-temperature single-crystal X-ray data. These isostructural compounds crystallize with two formula units in space group P4/nmm of the tetragonal system. Each An atom (An = U or Np) is coordinated to four O and four P atoms in a distorted square antiprism; each Cu atom is coordinated to four...

The crystal structure of the orthorhombic and tetragonal phases of La(Ba2-xLax)Cu3-yO6+x/2-y+z are determined on twinned crystals. The orthorhombic structure, obtained for low x, is close to the regular Y-Ba-Cu-O type (twin a * b * c-b * a * c), but is highly copper deficient on the Cu(1) site (~ 30 %). The local correlations (03BE ~ 20 Å) between copper atoms and vacancies, as deduced from X-r...