3 research outputs found
Spin-Hall-Active Platinum Thin Films Grown Via Atomic Layer Deposition
We study the magnetoresistance of yttrium iron garnet/Pt heterostructures in
which the Pt layer was grown via atomic layer deposition (ALD).
Magnetotransport experiments in three orthogonal rotation planes reveal the
hallmark features of spin Hall magnetoresistance. We estimate the spin
transport parameters by comparing the magnitude of the magnetoresistance in
samples with different Pt thicknesses. We compare the spin Hall angle and the
spin diffusion length of the ALD Pt layers to the values reported for
high-quality sputter-deposited Pt films. The spin diffusion length of 1.5nm
agrees well with platinum thin films reported in the literature, whereas the
spin Hall magnetoresistance is
approximately a factor of 20 smaller compared to that of our sputter-deposited
films. Our results demonstrate that ALD allows fabricating spin-Hall-active Pt
films of suitable quality for use in spin transport structures. This work
provides the basis to establish conformal ALD coatings for arbitrary surface
geometries with spin-Hall-active metals and could lead to 3D spintronic devices
in the future.Comment: 11 pages, 3 figure
Functional Incorporation of Integrins into Solid Supported Membranes on Ultrathin Films of Cellulose: Impact on Adhesion
Biomimetic models of cell surfaces were designed to study the physical basis of cell adhesion. Vesicles bearing reconstituted blood platelet integrin receptors α(IIb)β(3) were spread on ultrathin films of cellulose, forming continuous supported membranes. One fraction of the integrin receptors, which were facing their extracellular domain toward the aqueous phase, were mobile, exhibiting a diffusion constant of 0.6 μm(2) s(−1). The functionality of receptors on bare glass and on cellulose cushions was compared by measuring adhesion strength to giant vesicles. The vesicles contained lipid-coupled cyclic hexapeptides that are specifically recognized by integrin α(IIb)β(3). To mimic the steric repulsion forces of the cell glycocalix, lipids with polyethylene glycol headgroups were incorporated into the vesicles. The free adhesion energy per unit area Δg(ad) was determined by micro-interferometric analysis of the vesicle's contour near the membrane surface in terms of the equilibrium of the elastic forces. By accounting for the reduction of the adhesion strength by the repellers and from measuring the density of receptors one could estimate the specific receptor ligand binding energy. We estimate the receptor-ligand binding energy to be 10 k(B)T under bioanalogue conditions