31 research outputs found
Optimized fabrication of high quality La0.67Sr0.33MnO3 thin films considering all essential characteristics
In this article, an overview of the fabrication and properties of high
quality La0.67Sr0.33MnO3 (LSMO) thin films is given. A high quality LSMO film
combines a smooth surface morphology with a large magnetization and a small
residual resistivity, while avoiding precipitates and surface segregation. In
literature, typically only a few of these issues are adressed. We therefore
present a thorough characterization of our films, which were grown by pulsed
laser deposition. The films were characterized with reflection high energy
electron diffraction, atomic force microscopy, x-ray diffraction, magnetization
and transport measurements, x-ray photoelectron spectroscopy and scanning
transmission electron microscopy. The films have a saturation magnetization of
4.0 {\mu}B/Mn, a Curie temperature of 350 K and a residual resistivity of 60
{\mu}{\Omega}cm. These results indicate that high quality films, combining both
large magnetization and small residual resistivity, were realized. A comparison
between different samples presented in literature shows that focussing on a
single property is insufficient for the optimization of the deposition process.
For high quality films, all properties have to be adressed. For LSMO devices,
the thin film quality is crucial for the device performance. Therefore, this
research is important for the application of LSMO in devices.Comment: Accepted for publication in Journal of Physics D - Applied Physic
Misfit Strain Accommodation in Epitaxial ABO3 Perovskites: Lattice Rotations and Lattice Modulations
We present a study of the lattice response to the compressive and tensile
biaxial stress in La0.67Sr0.33MnO3 (LSMO) and SrRuO3 (SRO) thin films grown on
a variety of single crystal substrates: SrTiO3, DyScO3, NdGaO3 and
(La,Sr)(Al,Ta)O3. The results show, that in thin films under misfit strain,
both SRO and LSMO lattices, which in bulk form have orthorhombic (SRO) and
rhombohedral (LSMO) structures, assume unit cells that are monoclinic under
compressive stress and tetragonal under tensile stress. The applied stress
effectively modifies the BO6 octahedra rotations, which degree and direction
can be controlled by magnitude and sign of the misfit strain. Such lattice
distortions change the B-O-B bond angles and therefore are expected to affect
magnetic and electronic properties of the ABO3 perovskites.Comment: Submitted to Phys. Rev. B 13 pages, 9 figure
Towards Oxide Electronics:a Roadmap
At the end of a rush lasting over half a century, in which CMOS technology has been experiencing a constant and breathtaking increase of device speed and density, Moore's law is approaching the insurmountable barrier given by the ultimate atomic nature of matter. A major challenge for 21st century scientists is finding novel strategies, concepts and materials for replacing silicon-based CMOS semiconductor technologies and guaranteeing a continued and steady technological progress in next decades. Among the materials classes candidate to contribute to this momentous challenge, oxide films and heterostructures are a particularly appealing hunting ground. The vastity, intended in pure chemical terms, of this class of compounds, the complexity of their correlated behaviour, and the wealth of functional properties they display, has already made these systems the subject of choice, worldwide, of a strongly networked, dynamic and interdisciplinary research community. Oxide science and technology has been the target of a wide four-year project, named Towards Oxide-Based Electronics (TO-BE), that has been recently running in Europe and has involved as participants several hundred scientists from 29 EU countries. In this review and perspective paper, published as a final deliverable of the TO-BE Action, the opportunities of oxides as future electronic materials for Information and Communication Technologies ICT and Energy are discussed. The paper is organized as a set of contributions, all selected and ordered as individual building blocks of a wider general scheme. After a brief preface by the editors and an introductory contribution, two sections follow. The first is mainly devoted to providing a perspective on the latest theoretical and experimental methods that are employed to investigate oxides and to produce oxide-based films, heterostructures and devices. In the second, all contributions are dedicated to different specific fields of applications of oxide thin films and heterostructures, in sectors as data storage and computing, optics and plasmonics, magnonics, energy conversion and harvesting, and power electronics
Chemical vapour deposition synthetic diamond: materials, technology and applications
Substantial developments have been achieved in the synthesis of chemical
vapour deposition (CVD) diamond in recent years, providing engineers and
designers with access to a large range of new diamond materials. CVD diamond
has a number of outstanding material properties that can enable exceptional
performance in applications as diverse as medical diagnostics, water treatment,
radiation detection, high power electronics, consumer audio, magnetometry and
novel lasers. Often the material is synthesized in planar form, however
non-planar geometries are also possible and enable a number of key
applications. This article reviews the material properties and characteristics
of single crystal and polycrystalline CVD diamond, and how these can be
utilized, focusing particularly on optics, electronics and electrochemistry. It
also summarizes how CVD diamond can be tailored for specific applications,
based on the ability to synthesize a consistent and engineered high performance
product.Comment: 51 pages, 16 figure
Fabrication of piezodriven, free-standing, all-oxide heteroepitaxial cantilevers on silicon
We report on the fabrication and mechanical properties of all-oxide, free-standing, heteroepitaxial, piezoelectric, microelectromechanical systems (MEMS) on silicon, using PbZr0.52Ti0.48O3 as the key functional material. The fabrication was enabled by the development of an epitaxial lift-off strategy for the patterning of multilayer oxide heterostructures grown on Si(001), employing a high temperature stable, sacrificial oxide template mask to obtain freestanding cantilever MEMS devices after substrate etching. All cantilevers, with lengths in the range 25–325 μm, width 50 μm, and total thickness of 300 nm, can be actuated by an external AC-bias. For lengths 50–125 μm, the second order bending mode formed the dominant resonance, whereas for the other lengths different or multiple modes were present