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The exploration of metal–insulator transitions to produce field-induced reversible resistive switching effects has been a longstanding pursuit in materials science. Although the resistive switching effect in strongly correlated oxides is often associated with the creation or annihilation of oxygen vacancies, the underlying mechanisms behind this phenomenon are complex and, in many cases, still not clear. This study focuses on the analysis of the superconducting performance of cuprate YBa 2 Cu 3 O 7−δ (YBCO) devices switched to different resistive states through gate voltage pulses. The goal is to evaluate the effect of field-induced oxygen diffusion on the magnetic field and angular dependence of the critical current density and identify the role of induced defects in the switching performance. Transition electron microscopy measurements indicate that field-induced transition to high resistance states occurs through the generation of YBa 2 Cu 4 O 7 (Y124) intergrowths with a large amount of oxygen vacancies, in agreement with the obtained critical current density dependences. These results have significant implications for better understanding the mechanisms of field-induced oxygen doping in cuprate superconductors and their role on the superconducting performance.

Double perovskite oxides are of interest because of their electric, magnetic, and elastic properties; however, these properties are strongly dependent on the ordered arrangement of cations in the double perovskite structure. Therefore, many efforts have been made to improve the level of cationic ordering to obtain optimal properties while suppressing antisite defect formation. Here, epitaxial double perovskite La2CoMnO6 thin films were grown on top of (001)-STO oriented substrates by a polymer-assisted deposition chemical solution approach. Confirmation of the achievement of full Co/Mn cationic ordering was found by scanning transmission electron microscopy (STEM) measurements; EELS maps indicated the ordered occupancy of B–B′ sites by Co/Mn cations. As a result, optimal magnetic properties (Msat ≈ 6 µB/f.u. and Tc ≈ 230 K) are obtained. We show that the slow growth rates that occur close to thermodynamic equilibrium conditions in chemical solution methods represent an advantageous alternative to physical deposition methods for the preparation of oxide thin films in which complex cationic ordering is involved.

The annealing process is an important step common to epitaxial films prepared by chemical solution deposition methods. It is so because the final microstructure of the films can be severely affected by the precise features of the thermal processing. In this work we analyze the structural and magnetic properties of double perovskite La2CoMnO6 and La2NiMnO6 epitaxial thin films prepared by polymer-assisted deposition (PAD) and crystallized by rapid thermal annealing (RTA). It is found that samples prepared by RTA have similar values of saturation magnetization and Curie temperature to their counterparts prepared by using conventional thermal annealing (CTA) processes, thus indicating low influence of the heating rates on the B-B’ site cationic ordering of the A2BB’O6 double perovskite structure. However, a deeper analysis of the magnetic behavior suggested some differences in the actual microstructure of the films.

Understanding the origin and mechanisms of magnetic damping in complex oxide materials is crucial for optimizing spin dynamics and tailoring their properties for specific spintronic applications. Ferromagnetic resonance spectroscopy (FMR) technique has been used to investigate the magnetic damping of multiple La2/3Sr1/3MnO3 (LSMO) epitaxial thin films with similar thickness and identical DC magnetic properties. However, the dynamic magnetic properties exhibit noticeable variations among samples. Microstructural analyses using X‐ray diffraction (XRD) and atomic force microscopy (AFM), confirm that the samples are structurally identical, except for minute differences in the miscut angles of the substrates. Nevertheless, when examining the samples using backscattered electron (BSE) images in scanning electron microscopy (SEM), significant disparities in the twin distribution are observed. These variations in the twin distribution directly correlate with the observed differences in the damping values. A careful image analysis of BSE images allows to demonstrate that the increase of damping is due to the pinning of the magnetization in the twin boundaries. Ferromagnetic resonance spectroscopy is used to study magnetic damping in epitaxial La2/3Sr1/3MnO3 thin films. Backscattering scanning electron microscopy images show significant disparities in the twin's distribution in otherwise identical samples, which correlate with changes in damping values. A meticulous analysis of these images shows that the increased damping is the result of magnetization pinning at twin's boundaries.

The synthesis of a terbium-based 2D metal–organic framework (MOF), of formula [Tb(MeCOO)(PhCOO)2] (1), a crystalline material formed by neutral nanosheets held together by Van der Waals interactions, is presented. The material can be easily exfoliated by sonication and deposited onto different substrates. Uniform distributions of Tb-2D MOF flakes onto silicon were obtained by spin-coating. We report the luminescent and magnetic properties of the deposited flakes compared with those of the bulk. Complex 1 is luminescent in the visible and has a sizeable quantum yield of QY = 61% upon excitation at 280 nm. Photoluminescence measurements performed using a micro-Raman set up allowed us to characterize the luminescent spectra of individual flakes on silicon. Magnetization measurements of flakes-on-silicon with the applied magnetic field in-plane and out-of-plane display anisotropy. Ac susceptibility measurements show that 1 in bulk exhibits field-induced slow relaxation of the magnetization through two relaxation paths and the slowest one, with a relaxation time of τlf ≈ 0.5 s, is assigned to a direct process mechanism. The reported exfoliation of lanthanide 2D-MOFs onto substrates is an attractive approach for the development of multifunctional materials and devices for different applications.

This study reports on the epitaxial growth and structural characterization of ultrathin NiO‐films deposited by magnetron sputtering on La2/3Sr1/3MnO3 (LSMO) films grown on SrTiO3 (STO) substrates with (001)‐ and (111)‐orientations. X‐ray diffraction and atomic‐force microscopy show that all NiO layers are single‐phase, face‐centered pseudo‐cubic, atomically smooth, root‐main‐square (RMS) surface roughness <0.15 nm, and form abrupt interfaces with LSMO. High‐resolution reciprocal‐space maps reveal that the films are largely relaxed, but exhibit a slight compressive distortion, yielding unit‐cell volumes larger than bulk NiO. Despite a nominal ≈7% lattice mismatch, aberration‐corrected scanning transmission electron microscopy uncovers an array of misfit dislocations at the NiO/LSMO interface that help to accommodate strain allowing epitaxial growth of NiO layers. On (001)‐oriented samples, the four antiferromagnetic T‐domains are oblique to the sample plane, while on the (111) case, one lies in‐plane. This in‐plane domain shows greater spacing between ferromagnetic (111) planes due to unit cell distortion. This structural domain splitting can influence magnetic order and spin transmission efficiency, highlighting crystallographic orientation as a key factor in designing high‐performance spintronic devices. Antiferromagnets (AF) are a promising platform for high‐speed, low‐power spintronic devices. AF also play a relevant role for interface‐engineering in ferromagnet/normal‐metal (FM/NM) heterostructures to enhance spin‐current transmission. In this role, controlling the Néel vector orientation is key. The findings demonstrate a structural approach to manipulate AF domains in insulating NiO, paving the way for improved spin‐current coupling in FM/AF/NM devices.

Combined sandstone petrography and heavy mineral analysis allow to decipher different sediment routing systems that could not be resolved by one method alone in the South Pyrenean foreland basin. We apply this approach to deltaic and alluvial deposits of the southern part of the Jaca basin, and in the time equivalent systems of the nearby Ainsa and Ebro basins, in order to unravel the evolution of source areas and the fluvial drainage from the Eocene to the Miocene. Our study allows the identification of four petrofacies and five heavy-mineral suites, which evidence the interplay of distinct routing systems, controlled by the emergence of tectonic structures. Two distinct axially-fed systems from the east coexisted in the fluvial Campodarbe Formation of the southern Jaca basin that were progressively replaced from east to west by transverse-fed systems sourced from northern source areas. In the late stages of evolution, the Ebro autochthonous basin and the Jaca piggy-back basin received detritus from source areas directly north of the basin from the Axial Zone and from the Basque Pyrenees. Coupling sandstone petrography with heavy mineral provenance analysis allows challenging the existing model of the South Pyrenean sediment dispersal, highlighting the relevance of this approach in source-to-sink studies.

Control of magnetization reversal processes is a key issue for the implementation of magnetic materials in technological applications. The modulation of shape magnetic anisotropy in nanowire structures with a high aspect ratio is an efficient way to tune sharp in‐plane magnetic switching. However, control of fast magnetization reversal processes induced by perpendicular magnetic fields is much more challenging. Here, tunable sharp magnetoresistance changes, triggered by out‐of‐plane  magnetic fields, are demonstrated in thin permalloy strips grown on LaAlO3 single crystal substrates. Micromagnetic simulations are used to evaluate the resistance changes of the strips at different applied field values and directions and correlate them with the magnetic domain distribution. The experimentally observed sharp magnetic switching, tailored by the shape anisotropy of the strips, is properly accounted for by numerical simulations when considering a substrate‐induced uniaxial magnetic anisotropy. These results are promising for the design of magnetic sensors and other advanced magnetoresistive devices working with perpendicular magnetic fields by using simple structures. Permalloy strips with substrate‐induced uniaxial anisotropy offer the possiblity to generate sharp magnetoresitance changes triggered by low out‐of‐plane magnetic fields. Sharp magnetization reversals tailored by the shape anisotropy of the strips are potentially useful for sensing and advanced magnetoresistive devices.

Graphene is a 2D material with potential for almost any purpose, thanks to a combination of excellent characteristics, e.g. high electrical conductivity. Graphene grown on SiC wafers is one of the promising routes for graphene integration into planar technology electronic applications. Synthesis is based on the decomposition of a SiC single crystal surface at high temperature, where Si-terminated SiC substrates require the formation of the C buffer layer. In spite of numerous experimental and theoretical works the understanding and control upon crucial factors such as step and terrace stability or surface roughening is far from been fully comprehended and then technologically optimized. We present experimental results on the deposition of graphene onto Si-terminated 6H-SiC. We analyze the effect of ex situ and in situ conditionings of the SiC surface in the thermal decomposition and reconstruction of the SiC terraces, toward higher control upon the growth process of graphene films.

In this article we demonstrate that a migration of iodine species and chemical transformation in a moist environment induced by a voltage-biased Pt electrode is able to alter the color and degree of charge transfer in a layer of the 2D organic molecular metal (BEDO-TTF) 2.4 I 3 [BEDO = bis(ethylenedioxy)tetrathiafulvalene] self-assembled at the surface of a polycarbonate film. These effects produce a reversible electrochromic behavior of the layer with low operating voltages and fast operation times. Adjuvant with electrochromism, this flexible material exhibits rectifying behavior whose I-V curves are dependent on the voltage sweep directions. These results open new possibilities for the design and fabrication of organic flexible materials for soft electrochromic and rectifying components. The easy working principle ensures reliability, low power consumption, and versatility through its implementation into simple devices. Such working principle has been confirmed by temperature dependent resistance measurements, X-Ray, EDX-SEM, and conducting-AFM studies. Molecular metal: dual functional devices enabled Migration and chemical transformation of iodine species in the organic salt has been utilized to make dual functional devices that can operate at low voltages. An international team led by Dr. Eden Steven from Florida State University, USA and Elena Laukhina from Ciber-BBN (ICMAB-CSIC), Spain develops flexible electrochromic and rectifying components based on bi-layered thin films of a molecular metal. The thin film consists of a thin polycarbonate substrate and a metallic triiodide salt of an organic molecule BEDO-TTF which undergoes losses or restore of I3- anions under forward or reverse biases in the presence of water, respectively, resulting in discoloration/coloration and electrical rectifying behavior. The simple working principle and the versatile functionalities shown here enable promising design and fabrication of organic electrochromic and rectifying devices in the near future.