Effect of substrates on epitaxy of Bi4Ti3O12 thin films by dipping—pyrolysis process

Bismuth titanate (Bi₄Ti₃O₁₂) thin films have been prepared on various substrates by the dipping—pyrolysis process using metal naphthenates as starting materials. The crystallinity and in-plane alignment of the films are analysed by X-ray diffraction θ-2θ scans and β scans (polar diagrams), respectively. Highly c-axis-oriented Bi₄Ti₃O₁₂ thin films with smooth surfaces are obtained by heat treatment at 750°C on SrTiO₃ (100), LaAlO₃ (100) and MgO (100) substrates, while films grown on Si (100) exhibit polycrystalline characteristics. The fluctuation of in-plane alignment of epitaxially grown films depends on the lattice-misfit values between the films and the substrates used; Bi₄Ti₃O₁₂ films on MgO shows the largest full width at half maximum values in their β scans.     

Effect of (n, γ) and (n, α) reactions of framework atoms on the (n, γ) recoils in Ba and Cs cations in high-silica zeolites

The effects of (n, γ) and (n, α) reactions of framework atoms on the fate of (n, γ) recoil species ¹³¹Ba²⁺ and ¹³⁴Cs⁺ from Ba²⁺ and Cs⁺ loaded in high-silica aluminosilicate and borosilicate zeolites (boron-zeotypes) have been studied. Studies were made of the recoil from “open to locked-in” and “locked-in to open” sites. In open to locked-in recoil, target ions were eluted with efficiencies of 90% where only (n, γ) processes were in operation, but in the presence of (n, γ) and (n, α) reactions, the efficiency fell to 80%. For locked-in to open site recoil, the corresponding efficiencies were in the ranges 50–60% and 40–50%. The effect of calcination temperature on the exchange of cations present was also ascertained. The high-silica zeolites used were synthesized according to published methods and were characterized by XRD, i.r., SEM, and t.g.-d.t.g./d.s.c. techniques, and all were found to be crystalline. In boron-zeotype materials, the magnitude of (n, α) damage was increased by the use of ¹⁰B isotope.