Strain-induced effects on the magnetic and electronic properties of epitaxial Fe${}_{1-x}$Co${}_x$Si thin films

Abstract

We have investigated the Co-doping dependence of the structural, transport, and magnetic properties of ε-FeCoSi epilayers grown by molecular beam epitaxy on silicon (111) substrates. Low energy electron diffraction, atomic force microscopy, X-ray diffraction, and high resolution transmission electron microscopy studies have confirmed the growth of phase-pure, defect-free ε-FeCoSi epitaxial films with a surface roughness of ~1 nm. These epilayers are strained due to lattice mismatch with the substrate, deforming the cubic B20 lattice so that it becomes rhombohedral. The temperature dependence of the resistivity changes as the Co concentration is increased, being semiconducting-like for low $x$ and metallic-like for x \gtrsim 0.3. The films exhibit the positive linear magnetoresistance that is characteristic of ε-FeCoSi below their magnetic ordering temperatures $T_{\mathrm{ord}}$, as well as the huge anomalous Hall effect of order several μΩcm. The ordering temperatures are higher than those observed in bulk, up to 77 K for x = 0.4. The saturation magnetic moment of the films varies as a function of Co doping, with a contribution of ~1 μ_{B}/ Co atom for x \lesssim 0.25. When taken in combination with the carrier density derived from the ordinary Hall effect, this signifies a highly spin-polarised electron gas in the low x, semiconducting regime.

9 pages, 10 figures

References in corpus (5)

• Electronic measurement and control of spin transport in Silicon
• Robust formation of skyrmions and topological Hall effect in epitaxial thin films of MnSi
• Coherent spin transport through a 350-micron-thick Silicon wafer
• Formation of a topological non-Fermi liquid in MnSi
• Giant generic topological Hall resistivity of MnSi under pressure

Cited by in corpus (12)

• Scattering mechanisms in textured FeGe thin films: magnetoresistance and the anomalous Hall effect
• Uniaxial pressure dependence of magnetic order in MnSi
• Thermoelectricity in correlated narrow-gap semiconductors
• Generic aspects of skyrmion lattices in chiral magnets
• Helical magnetic structure and the anomalous and topological Hall effects in epitaxial B20 Fe${}_{1-y}$Co${}_y$Ge films
• Manipulation of the spin helix in FeGe thin films and FeGe/Fe multilayers
• Skyrmions in thin films with easy-plane magnetocrystalline anisotropy
• Neutron study of in-plane skyrmions in MnSi thin films
• Chiral magnetic excitations in FeGe films
• A theory of skyrmion crystal formation
• Effective Field Model of Roughness in Magnetic Structures
• Giant enhancement of the skyrmion stability in a chemically strained helimagnet