DOI: 10.20350/digitalcsic/17879
title: Dataset supporting the publication “Spectroscopic insight into the structural and microstructural properties of La2Ce2O7 ceramics"

description: [Description of methods used for collection/generation of data] This collection of data have been collected by the methods listed below on ceramic pellet samples prepared as indicated in the publication “Is texture related to vacancy amount or ordering in La2Ce2O7?” by M. L. Sanjuán, R. I. Merino, A. K. Lakshya, and A. Chowdhury. (add doi and final reference). As a summary, the composition of the ceramics are 50 mol% La2O3 + 50 mol% CeO2 (referred to as LC50 in the following). Two different kind of powders were used: a nanopower prepared in MAPS (Materials’ Process - Structure Correlations) Laboratory, Metallurgical and Materials Engineering, Indian Institute of Technology Patna, Bihta, Bihar 801106, India (as in K. Singh, R. Kumar, A. Chowdhury, Synergistic effects ofultrasonication and ethanol washing in controlling the stoichiometry, phase-purity and morphology of rare-earthdoped ceria nanoparticles, Ultrason. Sonochem. 36 (2017)182–190, http://dx.doi.org/10.1016/j.ultsonch.2016.11.030.) that generated textured ceramic pellets (to be referred to in the following as TLC50_S####, where #### indicates the sintering temperature in ºC); and a commercial powder (from Trixotech Advanced Materials Pvt. Ltd., India) of the same composition that gave rise upon sintering to untextured pellets, (to be referred to in the following as ULC50_S####, where #### indicates the sintering temperature in ºC). They were prepared by shaping the powder into pellets using a uniaxial pressure of approximately ~750 MPa in a hardened stainless-steel die with a 12 mm diameter. Subsequently, the were pressureless sintering up to 1400 °C for a duration of 2 hours with a heating rate of 4 °C per minute. - Raman spectra: Raman spectra were recorded in a DILOR XY spectrometer equipped with a liquid nitrogen cooled CCD detector, using as excitation lines an Oxxius laser at 532 nm (model LCX-532S) and the 647, 568 and 488 nm lines of a mixed Kr+/Ar+ laser (model Melles Griot 643-RYP-A02). - Impedance spectra: A SI1260 Impedance Gain-Phase Analyzer (Solartron Instruments, Farnborough Hampshire UK) was used to measure the impedance in the frequency range from 0.1 to 107 Hz. Ag-paste electrodes (RS 186-3600, RS Components, UK) were painted on pellets of samples TLC50_S1400 and ULC50_S1400 in the temperature range from 200 to 400 °C. Two different electrode arrangements were used to measure the conductivity. ACROSS: Ag-paste electrodes were brush-painted on opposite faces of the pellet with around 0.25 cm2 area and 0.05 cm thick. This configuration was used for conductivity measurements across the pellets. ALONG: Another piece of sample TLC50_S1400 was used to get an estimate of the conductivity of the sample in the direction parallel to the pellet large surface. Two Ag-paste electrodes separated approximately 2 mm were painted on one side. The reported data were measured in an air atmosphere, starting from the higher temperature spectra. Relevant dimensions of samples and electrode positioning are given in the corresponding datafiles. - Optical transmittance and reflectance data: The UV-VIS-NIR hemispherical reflectance of the textured (TLC50) and untextured (ULC50) ceramic pellets sintered a 1000 °C, 1300 °C and 1400 °C was measured using a Cary5000 UV-VIS-NIR spectrophotometer (Agilent Technologies) equipped with the internal diffuse reflectance accessory. The reflectance was measured with reference with a Spectralon® large plate, on pellets around 0.5 mm thick. In-line transmission measurements were also performed on the same UV-VIS-NIR spectrophotometer.
description: [Methods for processing the data] - Raman spectra: Spectra were scaled to the same intensity of the main mode (fluorite-like mode). - Conductivity: The conductivity reported in the conductivity tables is calculated from sample Resistance data extracted from the Impedance Spectra (excluding electrode contribution), using the relationship between conductivity and resistance and the measured geometrical factor. Sample dimensions were measured with a digital caliper. The temperature was measured with a K-type thermocouple. - Optical transmittance and reflectance data are given as measured.