350 research outputs found
Structure and magnetic properties of Sm/Fe multilayers versus substrate temperature
Three Sm(2 Å)/Fe(3 Å) multilayers have been made using two electron beams in a high vacuum chamber onto very thin Kapton foils at different substrate temperatures, (Ts=40°C, 150°C and 230°C), with the same total thickness of 3000 Å. We have found that the substrate temperature strongly affects structure and magnetic properties of the samples. For a substrate temperature of 150°C the sample behaves as a three dimensional random magnet
Measurement of the surface susceptibility and the surface conductivity of atomically thin by spectroscopic ellipsometry
We show how to correctly extract from the ellipsometric data the surface
susceptibility and the surface conductivity that describe the optical
properties of monolayer . Theoretically, these parameters stem from
modelling a single-layer two-dimensional crystal as a surface current, a truly
two-dimensional model. Currently experimental practice is to consider this
model equivalent to a homogeneous slab with an effective thickness given by the
interlayer spacing of the exfoliating bulk material. We prove that the error in
the evaluation of the surface susceptibility of monolayer , owing to
the use of the slab model, is at least 10% or greater, a significant
discrepancy in the determination of the optical properties of this material.Comment: Keywords: Ellipsometry, graphene, MoS2, two dimensional crystals,
optical contrast, absorption, transition metal dichalcogenide monolayer
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