Low-Temperature Electrical Conductivity in Calcium-Doped Lithium Fluoride

Abstract

The vanatiates of praseodyniium through lutetium and yttrium had a prismatic morphology similar to the tetragonal phosphates and arscnatcs. Crystal size tendcd to increase with decreasing cation radius, a phenomenon similar to that observed with arscnates and phosphates grown by this technique. Crystal size was variable with maximum sizes on tlic order of 6 by 0.5 by 0.1 tnm wlicn the above procedure was used. Larger crystals arc possible with larger charges and slower cooling rates.Lanthanum vanadate, the only monoclinic rare-earth vanadate, formed crystals of poor quality with a platelike habit. Very few nuclei were produced, and largc but very thin crystals up to 1 cm square were found. Inclusions were extensive in the few crystals grown in tliesc experiments.The lead pyrovnnadatc flux described abovc was not suitable for the formation of cerium vanadate crystals. The principal crystal product was CeOz, which formed with cubic morphology. In a n attempt to enhance CcV04 formation, a flux of composition I'bO: VzO5 was tried which had a greater vanadium content than Journal of The American Ceramic Society-Discussions and Notes 53 9

Charge Carrier Accumulation in Lithium Fluoride Thin Films due to Li-Ion Absorption by Titania (100) Subsurface

“…On the basis of Y ion ∥ ( L ) = σ ion∞ L + Δ Y ion ∥ with σ ion∞ and Δ Y ion ∥ being bulk conductivity and excess conductance value (positive or negative for accumulation or depletion effect), respectively, we can deduce Δ Y ion ∥ and σ ion∞ from the linear relation of Y ion ∥ ( L ). The bulk conductivity σ ion∞ of LiF thin films at 190 °C is estimated from the slope to be about 2.8 × 10 –7 S/cm, which is consistent with the literature values of lightly doped single-crystal (10 –7 ∼10 –6 S/cm) at this temperature . Δ Y ion ∥ obtained from the intercept by extrapolating the linear fitting of Y ion ∥ ( L ) to L = 0 is positive, indicating ion carrier accumulation.…”