Stress Analysis and Q-Factor of Free-Standing (La,Sr)MnO Oxide Resonators.

High-sensitivity nanomechanical sensors are mostly based on silicon technology and related materials. The use of functional materials, such as complex oxides having strong interplay between structural, electronic, and magnetic properties, may open possibilities for developing new mechanical transduction schemes and for further enhancement of the device performances. The integration of these materials into micro/nano-electro-mechanical systems (MEMS/NEMS) is still at its very beginning and critical basic aspects related to the stress state and the quality factors of mechanical resonators made from epitaxial oxide thin films need to be investigated.

Roles of Defects and Sb-Doping in the Thermoelectric Properties of Full-Heusler FeTiSn.

The potential of FeTiSn full-Heusler compounds for thermoelectric applications has been suggested theoretically, but not yet proven experimentally, due to the difficulty in obtaining reproducible, homogeneous, phase-pure and defect-free samples. In this work, we studied FeTiSnSb polycrystals ( from 0 to 0.6), fabricated by high-frequency melting and long-time high-temperature annealing.

Planar Nanoactuators Based on VO Phase Transition.

Actuation at micro- and nanoscale often requires large displacements and applied forces. The high work energy density that lies inside many phase transitions is an appealing feature for developing new actuating schemes, especially if the transition is reversible and scalable into small actuating domains. Here, we show the fabrication of a planar nanomechanical actuator having chevron-type geometry and based on the phase transition of VO.

Macroscopic Versus Microscopic Schottky Barrier Determination at (Au/Pt)/Ge(100): Interfacial Local Modulation.

Macroscopic current-voltage measurements and nanoscopic ballistic electron emission spectroscopy (BEES) have been used to probe the Schottky barrier height (SBH) at metal/Ge(100) junctions for two metal electrodes (Au and Pt) and different metallization methods, specifically, thermal-vapor and laser-vapor deposition. Analysis of macroscopic current-voltage characteristics indicates that a SBH of 0.61-0.

Selective High-Frequency Mechanical Actuation Driven by the VO Electronic Instability.

Relaxation oscillators consist of periodic variations of a physical quantity triggered by a static excitation. They are a typical consequence of nonlinear dynamics and can be observed in a variety of systems. VO is a correlated oxide with a solid-state phase transition above room temperature, where both electrical resistance and lattice parameters undergo a drastic change in a narrow temperature range.

Giant oscillating thermopower at oxide interfaces.

Understanding the nature of charge carriers at the LaAlO3/SrTiO3 interface is one of the major open issues in the full comprehension of the charge confinement phenomenon in oxide heterostructures. Here, we investigate thermopower to study the electronic structure in LaAlO3/SrTiO3 at low temperature as a function of gate field. In particular, under large negative gate voltage, corresponding to the strongly depleted charge density regime, thermopower displays high negative values of the order of 10(4)-10(5) μVK(-1), oscillating at regular intervals as a function of the gate voltage.

Programmable mechanical resonances in MEMS by localized joule heating of phase change materials.

A programmable micromechanical resonator based on a VO2 thin film is reported. Multiple mechanical eigenfrequency states are programmed using Joule heating as local power source, gradually driving the phase transition of VO2 around its Metal-Insulator transition temperature. Phase coexistence of domains is used to tune the stiffness of the device via local control of internal stresses and mechanical properties.

Multistate memory devices based on free-standing VO2/TiO2 microstructures driven by Joule self-heating.

Two-terminal multistate memory elements based on VO(2)/TiO(2) thin film microcantilevers are reported. Volatile and non-volatile multiple resistance states are programmed by current pulses at temperatures within the hysteretic region of the metal-insulator transition of VO(2). The memory mechanism is based on current-induced creation of metallic clusters by self-heating of micrometric suspended regions and resistive reading via percolation.