Correction: A feasible pathway to stabilize monoclinic and tetragonal phase coexistence in barium titanate-based ceramics

Depto. de Física de MaterialesFac. de Ciencias FísicasTRUEpu

A feasible pathway to stabilize monoclinic and tetragonal phase coexistence in barium titanate-based ceramics

Multiphase coexistence has attracted significant interest in recent years because its control has entailed a significant breakthrough for the piezoelectric activity enhancement of lead-free piezoelectric oxides. However, the comprehension of phase coexistence still has many controversies including an adequate synthesis process and/or the role played by crystalline phases in functional properties. In this study, functional barium titanate [BaTiO_(3), (BTO)]-based materials with tunable functional properties were obtained by compositional modification via Bismuth (Bi) doping. Towards this aim, we systematically synthesized BTO-based materials by a sol-gel method, focusing on the control of Bi substitution in the BaTiO_(3) structure. In particular, we found that the substitution of Bi^(+3) leads to the stabilization of a monoclinic-tetragonal (M-T) phase boundary close to room temperature, which facilities the polarization process of the system. As a surprising result, we believe that the simple and cost-effective strategy and design principles described in this work open up the possibility of obtaining BTO-based lead-free ceramics with enhanced properties induced by the stabilization of the phase coexistence, expanding their application range

Comparative study of Cd tolerance and accumulation potential between Cakile maritima L. (halophyte) and Brassica juncea L.

In this work we evaluated Cd-phytoextraction ability of the halophyte Cakile maritima comparatively to the glycophyte Brassica juncea commonly recommended for phytoextraction. Seedlings were grown in nutrient solution added with 0–100 M Cd for 21 days. Cd impaired growth in B. juncea but had no significant impact on C. maritima. The halophyte C. maritima maintained also higher photosynthetic activity than the glycophyte B. juncea. Cd decreased leaf chlorophyll (Chl) and carotenoids concentrations as well as PSII efficiency (Fv/Fm, Fv/F0 and ˚PSII) in B. juncea while it increased intercellular CO2 concentration in this species. Shoot Cd content was higher in the halophyte C. maritima reaching 1365 g g−1dw at 100 M while it was 548 g g−1dw in B. juncea at the same dose. The translocation factor (TF) was higher for C. maritima than for B. juncea at all external Cd doses. It is concluded that the halophyte C. maritima could be considered as a promising plant material for Cd-phytoextraction.

Implementing a sol-gel route to adjust the structural and dielectric characteristics of Bi and Fe co-doped BaTiO3 ceramics

The present work explores the impact of Fe insertion on the physical properties of Ba0.95Bi0.05Ti1-xFexO3 (x = 0.025, 0.050, and 0.075) prepared via sol gel method. The resulting samples crystallize in the tetragonal structure with space group P4mm and their morphological features point out the variation of the microstructure with Fe content. In turn, the dielectric constant versus temperature plot reveals the existence of two transition phases: the first one is ferroelectric-paraelectric transition phase (TF-P) and the second one is ferroelectric orthorhombic - ferroelectric tetragonal phase (TO-T). Analysis of conductivity curves using Jonscher’s augmented equation (for x = 0.025) and Jonscher’s power law (for x = 0.075) suggests the Non-Overlapping Small Polaron Tunneling (NSPT) model as a conduction mechanism.publishe

Magnetocaloric Effect, Dielectric Relaxor Behavior, and Evidence for Direct Magnetodielectric Behavior in Ni 0.6 Zn 0.4 Al 0.5 Fe 1.5 O 4 Ceramics for High-Temperature Applications

International audienc

Low pressure experimental validation of low-dimensional analytical model for air–water two-phase transient flow in horizontal pipelines

10.3390/fluids6060220Fluids6622

Effects of partial manganese substitution by cobalt on the physical properties of Pr_(0.7)Sr_(0.3)Mn_(1-x)Co_(x)O_(3) (0 = x=0.15) manganites

© 2023 by the authors. Licensee MDPI This research was funded by the Tunisian Ministry of Higher Education and Scientific Research and by the Ministerio de Ciencia e Innovación (MCINN), grant number PID2021-123112OBC21.We have investigated the structural, magnetic, and electrical transport properties of Pr_(0.7)Sr_(0.3)Mn_(1-x)Co_(x) O_(3) nanopowders (x = 0, 0.05, 0.10 and 0.15). The Pechini Sol-gel method was used to synthesize these nanopowders. X-ray diffraction at room temperature shows that all the nano powders have an orthorhombic structure of Pnma space group crystallography. The average crystallite size of samples x = 0, 0.05, 0.10, and 0.15 are 33.78 nm, 29 nm, 33.61 nm, and 24.27 nm, respectively. Semi-quantitative chemical analysis by energy dispersive spectroscopy (EDS) confirms the expected stoichiometry of the sample. Magnetic measurements indicate that all samples show a ferromagnetic (FM) to paramagnetic (PM) transition with increasing temperature. The Curie temperature T-C gradually decreases (300 K, 270 K, 250 K, and 235 K for x = 0, 0.05, 0.10, and 0.15, respectively) with increasing Co concentrations. The M-H curves for all compounds reveal the PM behavior at 300 K, while the FM behavior characterizes the magnetic hysteresis at low temperature (5 K). The electrical resistivity measurements show that all compounds exhibit metallic behavior at low temperature (T T rho), for which the electronic transport can be explained by the variable range hopping model and the adiabatic small polaron hopping model. All samples have significant magnetoresistance (MR) values, even at room temperature. This presented research provides an innovative and practical approach to develop materials in several technological areas, such as ultra-high density magnetic recording and magneto resistive sensors.Ministerio de Ciencia e Innovación (MICINN)Tunisian Ministry of Higher Education and Scientific ResearchDepto. de Física de MaterialesFac. de Ciencias FísicasTRUEpu