6533b861fe1ef96bd12c56d3

RESEARCH PRODUCT

Structural, electronic, and magnetic properties of pseudomorphic CrFe nanostripes on W(110)

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We have grown pseudomorphic binary ${\mathrm{Cr}}_{1\ensuremath{-}x}{\mathrm{Fe}}_{x}$ alloy monolayers and sequences of Cr and Fe nanostripes on W(110) by molecular-beam epitaxy in ultrahigh vacuum. By coadsorption of Cr and Fe a pseudomorphic random CrFe alloy grows on the W(110) substrate. At a substrate temperature of $700\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ the CrFe alloy forms monolayer stripes in the step flow growth mode. We have measured magnetic properties of the monolayer alloy for $0.75\ensuremath{\leqslant}x\ensuremath{\leqslant}1$ using Kerr magnetometry. At a constant relative temperature $t=T∕{T}_{C}$ the saturation value of the Kerr rotation shows a maximum at $x=0.95$ and then decreases with decreasing Fe concentration vanishing at $x=0.75$. The Curie temperature ${T}_{C}$ shows a similar dependence on the composition. For $x\ensuremath{\geqslant}0.75$ scanning tunneling spectroscopy reveals conductivity maxima in the unoccupied local density of states near the Fermi level at constant energies independent of the Cr concentration. This behavior can be explained by a simple model of $d$-band filling, similar to the explanation of the Slater-Pauling curve for binary alloys. We demonstrate the growth of artificially heterogeneous structures using sequential deposition of Fe and Cr. The temperature dependence of the multistripe growth and interdiffusion is investigated. Appropriate deposition parameters allow the growth of a two-dimensional analogon to an Fe-Cr-Fe spin valve.