Distribution of Some Trivalent Ions between Melt and Single Crystals of Mg_2SiO_4 Grown by the Czochralski Method(Chemistry)

Partition coefficients for trace amounts of trivalent ions between artificial single crystals of Mg_2SiO_4 grown by the Czochralski method and the coexisting melt have been determined by neutron activation analysis. They are found to vary greatly with the amount of visible imperfections in the crystal and slightly with the concentration of the ions in the melt. Plots of the partition coefficients against ionic radius of the trace ions give a pattern which agrees qualitatively with that found in a natural olivine phenocryst-groundmass pair

Redetermination of the perovskite-type compound YRh3B revealing a Rh deficiency

In contrast with previous structural studies of ytterbium trirhodium boride, YbRh3B, that suggest a boron deficiency, the current redetermination of the crystal structure of YbRh3B revealed instead a rhodium deficiency with a refined composition of YbRh2.67 (2)B. In the ABX 3 perovskite-type structure, Yb, B and Rh are located on the A, B and X positions, respectively, with site symmetries of m m for the A and B sites, and 4/mm.m for the X site

Electrical conductivity measurement of fayalite under shock compression up to 56 GPa

The electrical conductivity measurements of single‐crystal fayalite are performed under shock wave compression in the pressure range 19.5–56 GPa. The electrical conductivity under shock compression increases by a factor of more than 10^(10) from 0 to 40 GPa. Over the range 19.5–42 GPa the specific conductivity σ can be closely described by log_(10)σ (S/m) = −4.65 + 0.15P (GPa). The conductivity versus pressure relation at room temperature is calculated by using measured values of the activation energy to correct the high‐temperature shock data to room temperature. After the effect of temperature is removed, the increase in conductivity with pressure approximately agrees with that measured under static pressure using a diamond anvil cell by Mao and Bell. Above pressures of ∼42 GPa the conductivity remains at a relatively high level of ∼100 S/m from 40 to 55 GPa