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© 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) well fitted by the relation rho = rho_(0) + rho_(2)T^(2) + rho_(4.5) T^(4.5) and semiconductor behavior above T rho (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 Research, Depto. de Física de Materiales, Fac. de Ciencias Físicas, TRUE, pub

© 2005 Elsevier B.V. All rights reserved. This work was supported by the EU (HPRN-CT-2001-00199) and MECD (MAT2003-00455)., b-doped GaSb ingots have been grown by the Bridgman method. The defect structure and compositional homogeneity of the crystals have been investigated by cathodoluminescence and X-ray microanalysis in the scanning electron microscope. The nature of the point defects has been found to depend on the position along the growth axis. Doping with Yb has been found to reduce the luminescence intensity of GaSb and no infrared emission related to intra-ionic transitions of the Yb_(3+) ions has been detected, EU, MECD, Depto. de Física de Materiales, Fac. de Ciencias Físicas, TRUE, pub

Workshop on Dielectrics in Microelectronics (10. 1999. Barcelona). © Elsevier Science Ltd. The authors would like to thank CAI de Implantación Iónica from the Complutense University in Madrid for technical assistance with the ECR-CVD system. This research was partially supported by the Spanish government under Grant no. TIC 98/0740., Cleaning of InP surfaces using electron cyclotron resonance (ECR) nitrogen plasmas has been studied. Electrical performance of Al/SiNx:H/InP structures has been analysed to determine the effect of the plasma cleaning. The SINx:H insulator layers are deposited at 200 degrees C using an ECR chemical vapour deposition technique. It is observed that a 30 s low-power (60 W) ECR N-2 plasma treatment of InP surface reduces the interface defects and improves the resistivity and breakdown held values of the SiNx:H. (C) 2000 Elsevier Science Ltd. All rights reserved., Spanish government, Depto. de Estructura de la Materia, Física Térmica y Electrónica, Fac. de Ciencias Físicas, TRUE, pub

© 2002 IOP Publishing Ltd. This work was partially supported by the Spanish Government under Grant No TIC98/0740., In this paper we report on the optimization of the SiNchi:H insulator, deposited by the electron cyclotron resonance (ECR) plasma method, as a dielectric for metal-insulator-semiconductor (MIS) structures built on an InP compound semiconductor. Two different MIS structures have been obtained in which the minimum of the interface trap density (D-it,D-min) at the insulator/InP interface attains values of device quality. In the first structure, a Al/SiN1.5:H/SiN1.6:H/InP dual-layer insulator was obtained and optimized after rapid thermal annealing treatment at 500 degreesC for 30s. After this treatment, the value of D-it,D-min was 9 x 10(11) cm(-2) eV(-1). In the second structure, the MIS structure was Al/SiN1.6:H/InP single-layer insulator, in which the InP surface was exposed to an N-2 plasma prior to the SiN1.6:H film deposition. In this case, the value of D-it.min was 1.6 x 10(12) cm(-2) eV(-1). Both types of structures were used as gate insulators on N-channel enhanced-mode MIS field-effect transistor test devices. From the dc output characteristics of the transistors, we obtain values for the electron channel mobility in the range 1550-1600 cm(-2) V-1 s(-1). This is a confirmation of the great potential of the ECR plasma method as a simple way to obtain device quality gate structures on InP without the use of passivation processes of the InP surface prior to the deposition of the gate dielectric, thus simplifying the whole device fabrication procedure., Spanish Government, Depto. de Estructura de la Materia, Física Térmica y Electrónica, Fac. de Ciencias Físicas, TRUE, pub

Workshop on Dielectrics in Microelectronics (10. 2000. Barcelona). © Elsevier Science Ltd., In this article, we study the influences of the rapid thermal annealing temperature and dielectric composition on the electrical characteristics of ECR-deposited silicon nitride SiNx:H-InP and SiNx:H-InGaAs interfaces. C-V deep level transient spectroscopy (DLTS) and conductance transient analysis have been applied. As for InP cases, DLTS results reveal that rapid thermal annealing application increases interfacial state density. In contrast, transient conductance measurements show that disorder induced gap-state (DIGS) damage density diminishes when RTA is applied. So, we can conclude that RTA treatments take out the insulator damage to the interface. In the InGaAs-n cases, we have observed that DIGS damage evolution with RTA temperature is opposite to the interfacial state density. This behaviour seems to suggest some temperature activated defect exchange between the insulator and the interface. Finally, as for the insulator composition influence on the interface quality of the InGaAs-n samples, DLTS results suggest that the intermediate x values (1.43 and 1.50) provide better interfaces than extreme x values. Conductance transient measurements add complementary information: insulator damage increases when x increases. Hence, x = 1.43 seems to be the best choice to improve the overall interface quality. (C) 2000 Elsevier Science Ltd. All rights reserved., Depto. de Estructura de la Materia, Física Térmica y Electrónica, Fac. de Ciencias Físicas, TRUE, pub

© American Institute of Physics. The authors would like to thank C. A. I. de Implantación Iónica from the Universidad Complutense in Madrid for technical assistance with the ECR-CVD system., A minimum interface trap density of 10(12) eV(-1) cm(-2) was obtained on SiNx:H/InP metalinsulator-semiconductor structures without InP surface passivation. The SiNx:H gate insulator was obtained by the electron cyclotron resonance plasma method. This insulator was deposited in a single vacuum run and was composed of two layers with different nitrogen-to-silicon ratios. The first layer deposited onto the InP was grown with a nitrogen-to-silicon ratio of N/Si=1.55, whereas the second one was grown with a N/Si ratio of N/Si = 1.43. After the insulator deposition, rapid thermal annealing of the devices was performed at a constant annealing time of 30 s. The interface trap density minimum value was obtained at an optimum annealing temperature of 500 degrees C. Higher annealing temperatures promote thermal degradation of the interface and a sharp increase in the trap density., Depto. de Estructura de la Materia, Física Térmica y Electrónica, Fac. de Ciencias Físicas, TRUE, pub

© 2010 American Institute of Physics. The study was partially supported by the local government Junta de Castilla y León under Grant No. VA018A06, and by the Spanish TEC2007 under Grant No. 63318 and TEC2008 under Grant No. 06988-C02-O2., The influence of the silicon nitride blocking layer thickness on the interface state densities (D(it)) of HfO(2)/SiN(x):H gate-stacks on n-type silicon have been analyzed. The blocking layer consisted of 3 to 7 nm thick silicon nitride films directly grown on the silicon substrates by electron-cyclotron-resonance assisted chemical-vapor-deposition. Afterwards, 12 nm thick hafnium oxide films were deposited by high-pressure reactive sputtering. Interface state densities were determined by deep-level transient spectroscopy (DLTS) and by the high and low frequency capacitance-voltage (HLCV) method. The HLCV measurements provide interface trap densities in the range of 10(11) cm(-2) eV(-1) for all the samples. However, a significant increase in about two orders of magnitude was obtained by DLTS for the thinnest silicon nitride barrier layers. In this work we probe that this increase is an artifact due to the effect of traps located at the internal interface existing between the HfO(2) and SiN(x):H films. Because charge trapping and discharging are tunneling assisted, these traps are more easily charged or discharged as lower the distance from this interface to the substrate, that is, as thinner the SiN(x):H blocking layer. The trapping/detrapping mechanisms increase the amplitude of the capacitance transient and, in consequence, the DLTS signal that have contributions not only from the insulator/substrate interface states but also from the HfO(2)/SiN(x):H interlayer traps., Junta de Castilla y León, Spanish TEC2007, Spanish TEC2008, Depto. de Estructura de la Materia, Física Térmica y Electrónica, Fac. de Ciencias Físicas, TRUE, pub

© 2004 IOP Publishing Ltd. This work has been supported by MCYT (Project MAT 2003-00455). DM acknowledges a grant from MCYT., Remote electron beam induced current (REBIC) and cathodoluminescence (CL) modes in the scanning electron microscope (SEM) have been used to investigate SnO2 sintered samples. The study of the electrically active boundaries present in the oxide shows a characteristic peak and trough (PAT) contrast after thermal treatments in oxygen. Temperature-dependent measurements of the REBIC contrast show the presence of a shallow defect level 60 meV below the conduction band. This level is asigned to oxygen species adsorbed on the defect-rich boundaries. Evolution of REBIC contrast of the grain boundaries with excitation density enabled us to perform local measurements of minority carrier diffusion length., MCYT, Depto. de Física de Materiales, Fac. de Ciencias Físicas, TRUE, pub

This paper explores the impact of dysprosium (Dy) doping on structural, optical, and photocatalytic properties of tin oxide (SnO2) thin films fabricated via spray pyrolysis. Dysprosium doping levels ranged from 0 to 7 at%, and films were grown on glass substrates at 350 °C. X-ray diffraction (XRD) analysis revealed an increase in crystallite size with Dy doping, signifying improved crystalline quality. Simultaneously, dislocation density and strain decreased, indicating enhanced film quality. Texture coefficient (Tchkl) results showed a predominant crystal orientation along the (110) plane due to Dy doping. Optical band gap energy (Eg) decreased with Dy doping up to 5%. Urbach energy increased with Dy doping, suggesting atomic structural flaws and defects. Scanning electron microscopy (SEM) analysis revealed the presence of numerous micro-aggregates on the film's surface. Notably, the density of these micro-aggregates increased proportionally with higher Dy doping levels, particularly emphasizing the pronounced effect observed in SnO2:Dy 5% thin films. These findings underscore the potential of Dy-doped SnO2 thin films for advanced photocatalytic applications, with SnO2:Dy 5% exhibiting favorable properties and demonstrating a 90.99% degradation efficiency in three hours under solar irradiation.

© 2022. The Royal Society of Chemistry The present work has been supported by the Ministerio Español de Ciencia e Innovación (MICINN) through the projects: RTI2018-095856-B-C21 and RTI2018-095303-A-C52; Ministerio de Asuntos Económicos y Transformación Digital (MINECO) by PID2020-114192RB-C41; and Comunidad de Madrid, Spain, by S2018/NMT-4321 NANOMAGCOST and ‘‘Doctorados Industriales’’ project (IND2020/IND-17375), which is co-financed by the European Social Fund. A. S. acknowledges the financial support from the Comunidad de Madrid for an ‘‘Atracción de Talento Investigador’’ contract (2017-t2/IND5395). A. P. received funding from grant PRE2019-0875001234, Ministerio de Ciencia e Innovación (MICINN), Spain. R. E. Rojas-Hernandez acknowledges financial support from the Estonian Research Council (grants PSG-466)., 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., Ministerio de Ciencia e Innovación (MICINN) / FEDER, Ministerio de Ciencia e Innovación (MICINN), Estonian Research Council, Comunidad de Madrid, Depto. de Física de Materiales, Fac. de Ciencias Físicas, TRUE, pub

Protonic ceramic fuel cells (PCFCs), capable of harmonious and efficient conversion of chemical energy into electric power at reduced temperature enabled by fast proton conduction, are promising energy technology, which may radically re-define the whole way of energy conversion in the future, while their practical use is highly dependent on the availability of efficient key cell materials, i.e., electrolyte and electrodes, that should meet several important requirements, such as conductivity, stability, catalytic activity, compatibility, and cost. During the past two decades, complex oxides with the ABO3 perovskite or related structure have been extensively exploited as key materials in PCFCs, i.e., electrolyte and electrodes, due to their flexible composition with versatile properties. Rational design of perovskite and perovskite-related oxides with robust properties remains a pending research challenge, which makes in-depth understanding of the material engineering in PCFCs a specific focus of research. In this review, recent advances in the material engineering of perovskite oxides for PCFCs are summarized, and regulation strategies are presented, and applications as the electrodes and electrolyte are discussed. Importance is paid to exploiting the general rule of compositional engineering for amending the lattice structure, defect structure, and ionic transportation behavior of perovskite oxides, consequently providing useful guidance on the development of alternative perovskite materials for PCFCs and related fields.