84 research outputs found
Design and realization of a sputter deposition system for the \textit{in situ-} and \textit{in operando-}use in polarized neutron reflectometry experiments
We report on the realization of a sputter deposition system for the in situ-
and in operando-use in polarized neutron reflectometry experiments. Starting
with the scientific requirements, which define the general design
considerations, the external limitations and boundaries imposed by the
available space at a neutron beamline and by the neutron and vacuum
compatibility of the used materials, are assessed. The relevant aspects are
then accounted for in the realization of our highly mobile deposition system,
which was designed with a focus on a quick and simple installation and
removability at the beamline. Apart from the general design, the in-vacuum
components, the auxiliary equipment and the remote control via a computer, as
well as relevant safety aspects are presented in detail.Comment: Submitted for publication in Nuclear Inst. and Methods in Physics
Research, A. (1st revised version
Hetero-epitaxial EuO Interfaces Studied by Analytic Electron Microscopy
With nearly complete spin polarization, the ferromagnetic semiconductor
europium monoxide could enable next-generation spintronic devices by providing
efficient ohmic spin injection into silicon. Spin injection is greatly affected
by the quality of the interface between the injector and silicon. Here, we use
atomic-resolution scanning transmission electron microscopy in conjunction with
electron energy loss spectroscopy to directly image and chemically characterize
a series of EuO|Si and EuO|YAlO3 interfaces fabricated using different growth
conditions. We identify the presence of europium silicides and regions of
disorder at the EuO|Si interfaces, imperfections that could significantly
reduce spin injection efficiencies via spin-flip scattering
High-quality EuO thin films the easy way via topotactic transformation
Epitaxy is widely employed to create highly oriented crystalline films. A less appreciated, butnonetheless powerful means of creating such films is via topotactic transformation, in which achemical reaction transforms a single crystal of one phase into a single crystal of a differentphase, which inherits its orientation from the original crystal. Topotactic reactions may beapplied to epitactic films to substitute, add or remove ions to yield epitactic films of differentphases. Here we exploit a topotactic reduction reaction to provide a non-ultra-high vacuum(UHV) means of growing highly oriented single crystalline thin films of the easily overoxidizedhalf-metallic semiconductor europium monoxide (EuO) with a perfection rivallingthat of the best films of the same material grown by molecular-beam epitaxy or UHV pulsedlaserdeposition. As the technique only requires high-vacuum deposition equipment, it hasthe potential to drastically improve the accessibility of high-quality single crystalline films ofEuO as well as other difficult-to-synthesize compounds
- …