Mia Angelica Blea-Kirby

Thermal transport in tantalum oxide films for memristive applications

The thermal conductivity of amorphous TaOx memristive films having variable oxygen content is measured using time domain thermoreflectance. Thermal transport is described by a two-part model where the electrical contribution is quantified via the Wiedemann-Franz relation and the vibrational contribution by the minimum thermal conductivity limit for amorphous solids. The vibrational contribution remains constant near 0.9 W/mK regardless of oxygen concentration, while the electrical contribution varies from 0 to 3.3 W/mK. Thus, the dominant thermal carrier in TaOx switches between vibrations and charge carriers and is controllable either by oxygen content during deposition, or dynamically by field-induced charge state migration.

Phonon scattering mechanisms dictating the thermal conductivity of lead zirconate titanate (PbZr1−xTixO3) thin films across the compositional phase diagram

This work represents a thorough investigation of the thermal conductivity (κ) in both thin film and bulk PbZr1–xTixO3 (PZT) across the compositional phase diagram. Given the technological importance of PZT as a superb piezoelectric and ferroelectric material in devices and systems impacting a wide array of industries, this research serves to fill the gap in knowledge regarding the thermal properties. The thermal conductivities of both thin film and bulk PZT are found to vary by a considerable margin as a function of composition x. Additionally, we observe a discontinuity in κ in the vicinity of the morphotropic phase boundary (MPB, x = 0.48) where there is a 20%–25% decrease in κ in our thin film data, similar to that found in literature data for bulk PZT. The comparison between bulk and thin film materials highlights the sensitivity of κ to size effects such as film thickness and grain size even in disordered alloy/solid-solution materials. A model for the thermal conductivity of PZT as a function of com...

X-ray powder diffraction study of La2LiTaO6

The structure of La 2 LiTaO 6 has been derived from the powder X-ray powder diffraction (XRD) data. La 2 LiTaO 6 is monoclinic with unit-cell parameters a = 5.621(1) A, b = 5.776(1) A, c = 7.954(2) A, β = 90.34(2)°, space group P 2 1 / n (14), and Z = 2. The structure of La 2 LiTaO 6 is an ordered perovskite with alternating Li and Ta octahedra. A new set of powder XRD data ( d -spacing and intensity listing) has been generated to replace entry 00-039-0897 within the Powder Diffraction File. The newly elucidated structural data for La 2 LiTaO 6 shall facilitate quantitative analysis of this impurity phase which is often observed during synthesis of the fast-ion conductor phase Li 5 La 3 Ta 2 O 12 .