Crystal Lattice Volume Research Articles

Substitution effect of ionic conductivity in lithium ion conductor, LI 3INBR 6 − xCL x

Li 3InBr 6 − x Cl x was synthesized and the substitution effect on conductivity was investigated. Li 3InBr 6 − x Cl x was single phase at all compositions. The volume of crystal lattice was decreased with Cl content and the rate of the decrease changed at x = 3. The conductivity of Li 3InBr 6 − x Cl x had a maximum in Li 3InBr 3Cl 3 and its value was 1.2 × 10 −4 Scm − 1 at 300 K. The activation energy of the conduction was at the minimum around x = 3 and its value was 20 kJ mol − 1 . Phase transition temperature was lowered to be 285 K and the high conduction phase was stabilized by substitution Br with Cl. 7Li NMR spectra in Li 3InBr 3Cl 3 was sharp and it was confirmed that the diffusion of Li ion was fast at room temperature.

Effect of the lattice volume on the Al3+ ion conduction in NASICON type solid electrolyte

New trivalent Al3+ ion conductors with NASICON type structure, [Al0.2(Zr1–xTix)0.8]20/19Nb(PO4)3 and (Al1–xLax)4/19(1–x)Zr(16–19x)/19(1–x)Nb(PO4)3, were developed and their ion conducting properties were investigated. The lattice size of the NASICON type (AlxZr1–x)4/(4-x)Nb(PO4)3 series was successfully controlled by intentionally doping Ti4+ ion or La3+ ion in the crystal lattice, and the most suitable lattice size for the Al3+ ion conduction was identified from the relationship between the Al3+ ion conductivity and the lattice volume. The highest ion conductivity of 6.1×10−4 S·cm−1 at 600 °C was obtained for [Al0.2(Zr0.8Ti0.2)0.8]20/19Nb(PO4)3 among the NASICON type phosphate series prepared. Since the Al3+ ion conduction was dependent upon the crystal lattice size, it was demonstrated that the crystal lattice volume can be one of the key factors to optimize the ion conduction in the NASICON type structure.

Variation in emitter diffusion depth by TiSi/sub 2/ formation on polysilicon emitters of Si bipolar transistors

The emitter diffusion depth of wider emitters was found to be shallower than that of narrower emitters for transistors with a TiSi/sub 2/-formed in-situ phosphorus doped polysilicon (IDP) emitter. This dependence of emitter diffusion depth on emitter width W/sub E/ resulted in a large dependence of h/sub FE/ on W/sub E/. We found that the emitter diffusion in emitters with TiSi/sub 2/ formation was shallower than that in emitters without TiSi/sub 2/ formation. We conclude that the dependence of emitter diffusion depth on W/sub E/ is due to variation in phosphorus diffusivity caused by the TiSi/sub 2/ formation. We found by X-ray diffraction measurements that TiSi/sub 2/ formation reduced the crystal lattice volume of the IDP emitter layers by 0.2-0.30%. We attribute this reduction to a reduction in packing density due to a supersaturation of vacancies caused by the TiSi/sub 2/ formation. We believe that the vacancy supersaturation decreases the density of interstitials in the emitter regions, which decreases the emitter diffusion depth, and that the dependence of emitter diffusion depth on W/sub E/ is due to variations in the density of vacancies depending on W/sub E/.

Low limit of Mn 2+-activated cathodoluminescence of calcite: state of the art

In the literature, the lower limit for Mn 2+-activated cathodoluminescence (CL) of calcite is variously reputed to over a very wide range of values above 10 ppm Mn. Our spectroscopic investigations of the CL response in natural calcite reveal that below 10 ppm manganese content Mn 2+-activation is also present. Using the Quantitative High Resolution Spectral analysis of CL (QHRS-CL) an activation by Mn 2+ in the range of 700 ppb is proved, which cannot be determined visually. So, if not quenched, the minimum Mn 2+ content for Mn 2+-activation is one atom in the irradiated calcite crystal lattice volume. As the intrinsic (background blue) luminescence is used to determine non-altered biogenic calcite, the limit of Mn 2+-activation plays an important role in the interpretation of diagenetic processes. Our results of spectroscopic analyses require a revision of current opinions about the diagenesis of calcite as revealed by CL investigation.

Effects of temperature change and hydrogen content on titanium hydride crystal lattice volume

Temperature compressibility of hydride crystal lattice at low temperatures is found to be a function of hydrogen content. Occupation of both tetra- and octahedral sublattices by hydrogen results in a reduction of lattice compressibility with the temperature decrease.

Stress generation in thin Cu-Ti films in vacuum and hydrogen

Thin bilayer films of copper metal on titanium were sputter deposited on oxidized silicon wafers and annealed in vacuum and hydrogen ambients. Annealing in vacuum caused the bilayers to fail in tension, while the hydrogen annealed films did not fail. This observation is explained as stress generated due to crystal lattice volume changes and thermal expansion coefficients.

Helium dynamics in metal tritides I. The effect of helium from tritium decay on the desorption plateau pressure for La-Ni-Al tritides

Helium dynamics in La-Ni-Al tritides have been observed by measuring the plateau pressure decrease for the pressure of tritium in equilibrium with the solid as a function of helium composition. Calculations suggest that a crystal lattice volume expansion, caused by helium, stabilizes the tritide. Temperature cycling the helium-altered, tritium-saturated intermetallic partially restores the plateau pressure. These data are discussed in the context of immobile helium which can gain mobility as the tritide ages.

Thermal Generation of Vacancies and Substitutional Sites in Crystalline Polymers

It is proposed that differences between the thermal expansion of the macroscopic and crystal lattice volumes of crystalline polymers might be attributed to thermal generation of new substitutional sites. Consideration of the molecular arrangements suggests that vacancies can be generated within the lamellae at molecular folds and ends and at any point along some helical molecules. Part of the displaced molecule can be transported by point defects to the crystal surface where new sites are formed. Analysis of the available data for polyethylene shows the concentration of new sites (Δn/n) to be 2.2×10−2 at 100°C with an energy of creation of 0.2 eV and an entropy of creation of 5.3×10−4 eV/°K per site. It is pointed out that the phenomenon could account for the so-called glass transitions and is, therefore, closely related to the ``amorphous'' relaxations observed in crystalline polymers. The need for additional experiments is discussed.