Spatially Resolved Spectroscopic Extreme Ultraviolet Reflectometry for Laboratory Applications.

Spatially resolved extreme ultraviolet reflectometry is presented in application to a local characterization of thin non-uniform contamination layers. Sample reflectivity mapping is performed, demonstrating high chemical sensitivity of the technique. Amorphous Al₂O₃ and carbon are determined as the contaminants of the studied silicon wafer.

Spectromicroscopic insights for rational design of redox-based memristive devices.

The demand for highly scalable, low-power devices for data storage and logic operations is strongly stimulating research into resistive switching as a novel concept for future non-volatile memory devices. To meet technological requirements, it is imperative to have a set of material design rules based on fundamental material physics, but deriving such rules is proving challenging. Here, we elucidate both switching mechanism and failure mechanism in the valence-change model material SrTiO3, and on this basis we derive a design rule for failure-resistant devices.

Complex behaviour of vacancy point-defects in SrRuO3 thin films.

The behaviour of point defects in thin, epitaxial films of the oxide electrode SrRuO3 was probed by means of diffusion measurements. Thin-film SrRuO3 was deposited by means of pulsed laser deposition (PLD) on (100) oriented, undoped single crystal SrTiO3 substrates. (16)O/(18)O exchange anneals were employed to probe the behavior of oxygen vacancies.

Do dislocations act as atomic autobahns for oxygen in the perovskite oxide SrTiO3?

The transport properties of edge dislocations comprising a symmetrical 6° [001] tilt grain boundary in weakly acceptor-doped SrTiO3 were investigated by means of various experimental and computational techniques. Oxygen transport along the dislocation array was probed by means of (18)O/(16)O exchange experiments under (standard) oxidising conditions (pO2 = 5 × 10(-1) bar) and also under reducing conditions (pO2 = 7 × 10(-22) bar) at T = 973 K. In both cases, isotope profiles obtained by Secondary Ion Mass Spectrometry (SIMS) indicated no evidence of fast diffusion along the dislocation array.

Bulk mixed ion electron conduction in amorphous gallium oxide causes memristive behaviour.

In thin films of mixed ionic electronic conductors sandwiched by two ion-blocking electrodes, the homogeneous migration of ions and their polarization will modify the electronic carrier distribution across the conductor, thereby enabling homogeneous resistive switching. Here we report non-filamentary memristive switching based on the bulk oxide ion conductivity of amorphous GaOx (x~1.1) thin films.

Complex diffusion behavior of oxygen in nanocrystalline BaTiO3 ceramics.

(18)O/(16)O exchange annealing and subsequent Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) analysis is used to investigate oxygen transport in dense, nanocrystalline (average grain size d ≈ 300 nm) ceramics of nominally un-doped BaTiO3. Isotope penetration profiles are obtained as a function of temperature, 973 < T/K < 1173, at an oxygen activity aO2 = 0.20 and as a function of oxygen activity, 0.

A family of oxide ion conductors based on the ferroelectric perovskite Na0.5Bi0.5TiO3.

Oxide ion conductors find important technical applications in electrochemical devices such as solid-oxide fuel cells (SOFCs), oxygen separation membranes and sensors. Na0.5Bi0.

Activation volume tensor for oxygen-vacancy migration in strained CeO2 electrolytes.

We examine the effect of mechanical strain on the migration of oxygen vacancies in fluorite-structured ceria by means of density functional theory calculations. Different strain states (uniaxial, biaxial and isotropic) and strain magnitudes (up to ± 7%) are considered. From the calculations we extract the complete activation volume tensor for oxygen-vacancy migration in CeO(2), that is, all diagonal ΔV(mig,kk) and off-diagonal ΔV(mig,kl) tensor elements.

Ionic conduction in the SrTiO3|YSZ|SrTiO3 heterostructure.

Employing previously published experimental data, we analyse the enhanced conductivity of the heterostructure comprising yttria-stabilised zirconia (YSZ) and SrTiO3. We confirm that the heterostructure's conductivity arises from SrTiO3, and we conclude that it is exclusively ionic below T ∼ 540 K. The calculated excess conductance from space-charge layers is found to be negligible.

A low-temperature high resolution scanning tunneling microscope with a three-dimensional magnetic vector field operating in ultrahigh vacuum.

We present a low-temperature ultrahigh vacuum (UHV) scanning tunneling microscope setup with a combination of a superconducting solenoid coil and two split-pair magnets, providing a rotatable magnetic field up to 500 mT applicable in all spatial directions. An absolute field maximum of B=7 T(3 T) can be applied perpendicular (parallel) to the sample surface. The instrument is operated at a temperature of 4.