A Grease for Domain Walls Motion in HfO2-based Ferroelectrics

A large coercive field EC of HfO2 based ferroelectric devices poses critical performance issues in their applications as ferroelectric memories and ferroelectric field effect transistors. A new design to reduce EC by fabricating nanolaminate Hf0.5Zr0.5O2 / ZrO2 (HZZ) thin films is used, followed by an ensuing annealing process at a comparatively high temperature 700 °C. High-resolution electron microscopy imaging detects tetragonal-like domain walls between orthorhombic polar regions. These walls decrease the potential barrier of polarization reversal in HfO2 based films compared to the conventional domain walls with a single non-polar spacer, causing about a 40% decrease in EC. Capacitance vs. electric field measurements on HZZ thin film uncovered a substantial increase of dielectric permittivity near the EC compared to the conventional Hf0.5Zr0.5O2 thin film, justifying the higher mobility of domain walls in the developed HZZ film. The tetragonal-like regions served as grease easing the movement of the domain wall and reducing EC

NON-DESTRUCTIVE CONTROL OF CERAMICS BY THE RESULTS OF MEASURING ITS PERMITTIVITY IN THE MICROWAVE RANGE AND AT CONSTANT VOLTAGE

The results of evaluating the mechanical strength characteristics of ceramic samples by a non-destructive method based on measuring their permittivity are considered. In this case, measurements of the permittivity were carried out both in the microwave range on an 8-mm interferometer and in a constant electric field. Measurements in a constant electric field demonstrated the best information content and correlation with the ultimate strength in bending of the studied samples.

Application of quantitative electromagnetic technology to asses coating integrity of pipelines in México

There are several surface inspection methods to evaluate the integrity of the pipe coating, obtaining acceptable qualitative results in some soil types and low complexity pipeline systems. However, these methods do not determine the necessary parameters for a quantitative evaluation of coating quality. The Mexican Petroleum Institute has developed Surface Electromagnetic Pipeline Inspection (SEMPI) technology for the quantitative assessment of buried pipeline coating integrity. SEMPI is a theory-based technology that enables the development of instrumentation, field methodology, as well as data processing and interpretation techniques. The application of SEMPI consists of two stages: regional and local. The regional stage includes magnetic field, voltage and, soil resistivity (rs) measurements, where the main result is the determination of the electrical resistance of the coating (Tc) along the pipeline as an indicating parameter of the coating quality. A scale signalized from Tc data allows classifying the quality of pipe coating as good (green), fair (yellow) and poor (red). The local stage includes detailed electric field measurements of on anomalous pipeline sections (Tc < 50 Ohm.m2), locating damage in the coating with a detection accuracy of the ± 0.5 m. The equivalent unlined (holiday) area per meter of the inspected pipeline is calculated during the local stage. This work presents successful results from the implementation of regional and local stages of SEMPI technology in two pipelines located in the southeast region of Mexico.