Anionic and Magnetic Ordering in Rare Earth Tantalum Oxynitrides with an = 1 Ruddlesden-Popper Structure.

The new compounds RTaON with R = La, Ce, Nd, and Eu and 1.20 ≤ ≤ 2.81 have been obtained by a solid-state reaction between metal nitrides and oxides or oxynitrides under N gas at temperatures between 1200 and 1700 °C.

High-Temperature Synthesis of Ferromagnetic EuTa(O,N) with a Triple Perovskite Structure.

Europium tantalum perovskite oxynitrides were prepared by a new high-temperature solid-state synthesis under N or N/H gas. The nitrogen stoichiometry was tuned from 0.63 to 1.

Robust Antiferromagnetic FeRh Films on Mica.

FeRh shows an antiferromagnetic to ferromagnetic phase transition above room temperature, which permits its use as an antiferromagnetic memory element. However, its antiferromagnetic order is sensitive to small variations in crystallinity and composition, challenging its integration into flexible devices. Here, we show that flexible FeRh films of high crystalline quality can be synthesized by using mica as a substrate, followed by a mechanical exfoliation of the mica.

Ferroelectric Electroresistance after a Breakdown in Epitaxial HfZrO Tunnel Junctions.

The recent discovery of ferroelectricity in doped HfO has opened perspectives on the development of memristors based on ferroelectric switching, including ferroelectric tunnel junctions. In these devices, conductive channels are formed in a similar manner to junctions based on nonferroelectric oxides. The formation of the conductive channels does not preclude the presence of ferroelectric switching, but little is known about the device ferroelectric properties after conduction path formation or their impact on the electric modulation of the resistance state.

Control of up-to-down/down-to-up light-induced ferroelectric polarization reversal.

Light control of ferroelectric polarization is of interest for the exploitation of ferroelectric thin films in ultrafast data storage and logic functionalities. The rapidly oscillating electric field of light absorbed in a ferroelectric layer can suppress its polarization but cannot selectively reverse its direction. Here we take advantage of the built-in asymmetry at ferroelectric/electrode interfaces to break the up/down symmetry in uniaxial ferroelectrics to promote polarization reversal under illumination.

Clinical results and cost-effectiveness of radiofrequency and cyanoacrylate ablation compared with traditional surgical stripping for treating varicose veins.

Background: Disease of the venous system is an underappreciated public health problem. Minimally invasive treatments such as radiofrequency ablation (RFA) or cyanoacrylate adhesive ablation (CAA) have almost entirely replaced surgical stripping (SS) of the great and small saphenous veins. The purpose of the present study was to compare the outcomes at 3 years after SS, RFA, and CAA by assessing the incidence of complications and reinterventions and performing a cost-effectiveness analysis.

High-Temperature Synthesis and Dielectric Properties of LaTaON.

The development of new synthetic methodologies of perovskite oxynitrides is challenging but necessary for the search of new compounds and the investigation of new properties. Here, we report a new method of preparation of the perovskite LaTaON that has been investigated as a pigment and photocatalyst for water splitting. The synthesis proceeds through the solid-state reactions under N at 1500 °C between LaO, LaN, and TaN or between LaN and TaON, which are completed after 3 h and lead to sintered, highly crystalline samples with particle sizes up to 1 μm.

Electron-Phonon Coupling and Electron-Phonon Scattering in SrVO.

Understanding the physics of strongly correlated electronic systems has been a central issue in condensed matter physics for decades. In transition metal oxides, strong correlations characteristic of narrow d bands are at the origin of remarkable properties such as the opening of Mott gap, enhanced effective mass, and anomalous vibronic coupling, to mention a few. SrVO with V  in a 3d  electronic configuration is the simplest example of a 3D correlated metallic electronic system.

Non-volatile optical switch of resistance in photoferroelectric tunnel junctions.

In the quest for energy efficient and fast memory elements, optically controlled ferroelectric memories are promising candidates. Here, we show that, by taking advantage of the imprint electric field existing in the nanometric BaTiO films and their photovoltaic response at visible light, the polarization of suitably written domains can be reversed under illumination. We exploit this effect to trigger and measure the associate change of resistance in tunnel devices.

Platelet hyperaggregability and venous thrombosis risk: results from the RETROVE project.

The aim of the study was to determine whether platelet hyperaggregability correlates with short closure times (PFA-100) and if hyperaggregability is associated with the risk of venous thrombosis in a Spanish population. Case--control study (RETROVE project) involving 400 patients with venous thrombosis and 400 healthy controls. We determined platelet aggregation in platelet-rich plasma (PRP) by light transmission aggregometry.

Engineering Polar Oxynitrides: Hexagonal Perovskite BaWON.

Non-centrosymmetric polar compounds have important technological properties. Reported perovskite oxynitrides show centrosymmetric structures, and for some of them high permittivities have been observed and ascribed to local dipoles induced by partial order of nitride and oxide. Reported here is the first hexagonal perovskite oxynitride BaWON , which shows a polar 6H polytype.

Flexible Antiferromagnetic FeRh Tapes as Memory Elements.

The antiferromagnetic to ferromagnetic transition occurring above room temperature in FeRh is attracting interest for applications in spintronics, with perspectives for robust and untraceable data storage. Here, we show that FeRh films can be grown on a flexible metallic substrate (tape shaped), coated with a textured rock-salt MgO layer, suitable for large-scale applications. The FeRh tape displays a sharp antiferromagnetic to ferromagnetic transition at about 90 °C.

VAMP8 and serotonin transporter levels are associated with venous thrombosis risk in a Spanish female population. Results from the RETROVE Project.

Introduction: Platelet hyper-reactivity has been associated with thrombosis and high levels of human vesicle-associated membrane protein 8 (VAMP8) and serotonin transporter (SERT). Two polymorphisms (rs1010 of VAMP8 gene and in SERT gene (SLC6A4)) are associated with arterial thrombosis.

Aim: To determine if levels of serotonin, SERT and/or VAMP8 and these polymorphisms are associated with the risk of venous thrombosis.

Topochemical nitridation of SrFeMoO.

The topotactic nitridation of cation ordered, tetragonal Sr2FeMoO6 in NH3 at moderate temperatures leads to cubic, Fm3[combining macron]m double perovskite oxynitride Sr2FeMoO4.9N1.1 where double-exchange interactions determine ferromagnetic order with TC ≈ 100 K.

Complementary Resistive Switching Using Metal-Ferroelectric-Metal Tunnel Junctions.

Complementary resistive switching (CRS) devices are receiving attention because they can potentially solve the current-sneak and current-leakage problems of memory arrays based on resistive switching (RS) elements. It is shown here that a simple anti-serial connection of two ferroelectric tunnel junctions, based on BaTiO , with symmetric top metallic electrodes and a common, floating bottom nanometric film electrode, constitute a CRS memory element. It allows nonvolatile storage of binary states ("1" = "HRS+LRS" and "0" = "LRS+HRS"), where HRS (LRS) indicate the high (low) resistance state of each ferroelectric tunnel junction.

Epitaxial Integration on Si(001) of Ferroelectric HfZrO Capacitors with High Retention and Endurance.

Epitaxial ferroelectric HfZrO films have been successfully integrated in a capacitor heterostructure on Si(001). The orthorhombic HfZrO phase, [111] out-of-plane oriented, is stabilized in the films. The films present high remnant polarization P close to 20 μC/cm, rivaling with equivalent epitaxial films on single crystalline oxide substrates.

Cost-effectiveness of Carotid Surgery.

Background: The purpose of this study is to determinate the cost-effectiveness of carotid endarterectomy (CEA) versus transfemoral stenting (TFS) and transcervical stenting (TCS) in a short- and long-term basis in symptomatic and asymptomatic patients.

Methods: From January 2003 to December 2014, patients from the vascular department, with symptomatic or asymptomatic carotid stenosis, who were clinically and anatomically suitable for TFS, TCS, or CEA, were included. Prospective cost data for each individual procedure and complication during follow-up were obtained from the diagnosis-related group.

Short closure time values in PFA-100® are related to venous thrombotic risk. Results from the RETROVE Study.

Introduction: Platelets play a role in the pathophysiology of venous thromboembolism (VTE). Some studies have not found an association between VTE and platelet aggregation. The PFA-100® analyser is an in vitro assay for assessing primary haemostasis.

Control of Polar Orientation and Lattice Strain in Epitaxial BaTiO Films on Silicon.

Conventional strain engineering of epitaxial ferroelectric oxide thin films is based on the selection of substrates with a suitable lattice parameter. Here, we show that the variation of oxygen pressure during pulsed laser deposition is a flexible strain engineering method for epitaxial ferroelectric BaTiO films either on perovskite substrates or on Si(001) wafers. This unconventional growth strategy permits continuous tuning of strain up to high levels (ε > 0.

Control of the Polarization of Ferroelectric Capacitors by the Concurrent Action of Light and Adsorbates.

Ferroelectric perovskites hold promise of enhanced photovoltaic efficiency and photocatalytic activity. Consequently, the photoresponse of oxide ferroelectric thin films is an active field of research. In electrode/ferroelectric/electrode devices, internal charge in the ferroelectric, free charge in the electrodes, and buried adsorbates at interfaces combine to screen the ferroelectric polarization and to stabilize the polar state.

Magnetoresistance in Hybrid Pt/CoFeO Bilayers Controlled by Competing Spin Accumulation and Interfacial Chemical Reconstruction.

Pure spin currents have potential for use in energy-friendly spintronics. They can be generated by a flow of charge along a nonmagnetic metal with large spin-orbit coupling. This produces a spin accumulation at the surfaces, controllable by the magnetization of an adjacent ferromagnetic layer.

Tailoring Lattice Strain and Ferroelectric Polarization of Epitaxial BaTiO Thin Films on Si(001).

Ferroelectric BaTiO films with large polarization have been integrated with Si(001) by pulsed laser deposition. High quality c-oriented epitaxial films are obtained in a substrate temperature range of about 300 °C wide. The deposition temperature critically affects the growth kinetics and thermodynamics balance, resulting on a high impact in the strain of the BaTiO polar axis, which can exceed 2% in films thicker than 100 nm.

Hidden Magnetic States Emergent Under Electric Field, In A Room Temperature Composite Magnetoelectric Multiferroic.

The ability to control a magnetic phase with an electric field is of great current interest for a variety of low power electronics in which the magnetic state is used either for information storage or logic operations. Over the past several years, there has been a considerable amount of research on pathways to control the direction of magnetization with an electric field. More recently, an alternative pathway involving the change of the magnetic state (ferromagnet to antiferromagnet) has been proposed.

Competition between Polar and Nonpolar Lattice Distortions in Oxide Quantum Wells: New Critical Thickness at Polar Interfaces.

Two basic lattice distortions permeate the structural phase diagram of oxide perovskites: antiferrodistortive (AFD) rotations and tilts of the oxygen octahedral network and polar ferroelectric modes. With some notable exceptions, these two order parameters rarely coexist in a bulk crystal, and understanding their competition is a lively area of active research. Here we demonstrate, by using the LaAlO_{3}/SrTiO_{3} system as a test case, that quantum confinement can be a viable tool to shift the balance between AFD and polar modes and selectively stabilize one of the two phases.

Direct imaging of delayed magneto-dynamic modes induced by surface acoustic waves.

The magnetoelastic effect-the change of magnetic properties caused by the elastic deformation of a magnetic material-has been proposed as an alternative approach to magnetic fields for the low-power control of magnetization states of nanoelements since it avoids charge currents, which entail ohmic losses. Here, we have studied the effect of dynamic strain accompanying a surface acoustic wave on magnetic nanostructures in thermal equilibrium. We have developed an experimental technique based on stroboscopic X-ray microscopy that provides a pathway to the quantitative study of strain waves and magnetization at the nanoscale.