3-Dimensional analysis of flexoelectric twin structures in epitaxial WO3 thin films with TEM&STEM

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STEM & TEM analysis of ferroelastic twin structures in epitaxial WO3 thin film

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3-Dimensional Analysis of Ferroelastic Twin Structures in Epitaxial WO3 Thin Films with TEM&STEM

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Post-lithiation: a way to control the ionic conductivity of solid-state thin film electrolyte

Ionic conductivity is pivotal for solid-state battery performance. While the garnet oxide electrolyte Li7La3Zr2O12 (LLZO) boasts high ionic conductivity due to its distinct crystal structure and lithium-ion mobility, lithium loss during fabrication hampers its potential. In this study, we introduce a method that merges synthesis optimization with a post-lithiation process, enhancing LLZO's ionic conductivity. This approach compensates lithium loss with a gas-phase diffusion process, which stabilizes the cubic LLZO phase and amplifies its ionic conductivity by more than three orders of magnitude compared to electrolytes without post-lithiation. Through our comprehensive experimental procedure, we have conclusively determined that the film deposited at 700 °C and subsequently annealed at 700 °C with LiOH exhibits the highest conductivity, with a notable value of 1.11 × 10−2 S cm−1 at 200 °C. This is a significant boost compared to the as-deposited film (3.54 × 10−6 S cm−1 at 200 °C). Our findings present an additional approach to boosting lithium ion diffusion. The approach employed in this work has the potential to be applicable to films produced through other deposition methods, as it addresses the prevalent issue of lithium loss, a significant barrier to the utilization of lithium-rich thin films

Tuning Oxide Properties by Oxygen Vacancy Control During Growth and Annealing

Electrical, optical, and magnetic properties of oxide materials can often be controlled by varying the oxygen content. Here we outline two approaches for varying the oxygen content and provide concrete examples for tuning the electrical properties of SrTiO3-based heterostructures. In the first approach, the oxygen content is controlled by varying the deposition parameters during a pulsed laser deposition. In the second approach, the oxygen content is tuned by subjecting the samples to annealing in oxygen at elevated temperatures after the film growth. The approaches can be used for a wide range of oxides and nonoxide materials where the properties are sensitive to a change in the oxidation state. The approaches differ significantly from electrostatic gating, which is often used to change the electronic properties of confined electronic systems such as those observed in SrTiO3-based heterostructures. By controlling the oxygen vacancy concentration, we are able to control the carrier density over many orders of magnitude, even in nonconfined electronic systems. Moreover, properties can be controlled, which are not sensitive to the density of itinerant electrons

Engineering of Electromechanical Oxides by Symmetry Breaking

Abstract Complex oxides exhibit a wide range of fascinating functionalities, such as ferroelectricity, piezoelectricity, and pyroelectricity, which are indispensable for cutting‐edge electronics, energy, and information technologies. The intriguing physical properties of these complex oxides arise from the complex interplay between lattice, orbital, charge, and spin degrees of freedom. Here, it is reviewed how electromechanical properties can be achieved/improved by artificially breaking the symmetry of centrosymmetric oxides via engineering thermodynamic variables such as stress, strain, electric field, and chemical potentials. The mechanisms that have been utilized to break the inherent symmetry of conventional materials that lead to novel functionalities and applications are explored. It is highlighted that access to “hidden phases,” which otherwise are prohibited, could uncover opportunities to host exotic properties, such as piezoelectricity, pyroelectricity, etc. This review not only reports how to engineer intrinsically nonpolar and centrosymmetric oxides for emergent properties, but also has implications for manipulating polar functional materials for better performance

Blood cadmium and volume of uterine fibroids in premenopausal women

Abstract Background A number of studies have found associations between heavy metals and uterine fibroids, but the results are inconsistent. Here, we conducted this research to demonstrate the relationships between blood heavy metal concentrations and uterine fibroid volume as well as the rate of uterine fibroid presence. Methods In a cross-sectional study, we collected data from 308 premenopausal women aged 30–49 years in Seoul; uterine fibroids are ascertained by past history of myomectomy and pelvic ultrasonography. In the analytic phase, we first analyzed the presence of the fibroids and the concentrations of heavy metals via logistic regression. In subgroup analysis, we used simple and multiple linear regression analyses to examine the associations between heavy metals and uterine fibroid volume. Results There was no connection between the heavy metal concentrations and the presence of uterine fibroids, but the odds of women having fibroids were higher with three particular metals. In subgroup analysis, the association between blood cadmium concentrations and uterine fibroid volume was statistically significant (adjusted beta coefficient = 2.22, 95% confidential interval: 0.06–4.37). In contrast, blood mercury and lead concentrations were not significantly associated with uterine fibroid volume. Conclusions Our findings are the first that we know to report the association of blood cadmium concentrations with the volume of uterine fibroids. We expect that our findings will be used as evidence for supporting policies to improve premenopausal Korean women’s health