Structure and magnetism of MnGe thin films grown with a nonmagnetic CrSi template

Abstract

We report a method to grow B20 MnGe thin films using molecular-beam epitaxy, which employs an ultrathin CrSi template layer on Si(111). This layer is expected to be nonmagnetic, in contrast to MnSi and FeGe buffer layers that have been used previously. This template layer permits an investigation of the intrinsic properties of MnGe in the ultrathin-film limit without the influence of a neighboring magnetic layer. Single-phase MnGe(111) films were grown with thicknesses between 2 and 40 nm, which exhibited low interfacial roughnesses on the order of 0.6 nm. The films crystallized in a B20 structure with a small rhombohedral distortion. Magnetometry measurements in out-of-plane fields are consistent with a cone phase derived from helimagnetic order propagating along the film normal. However, an unexpected remanent moment develops below 35K, concomitant with features in the field dependence of the transport data. This provides indirect evidence for the presence of a low-temperature phase which has been identified by others as either a triple-Q topological spin-hedgehog lattice, or a multidomain single-Q helical state.

Main paper: 14 pages, 11 figures. Supplemental: 10 pages, 6 figures

References in corpus (11)

• Surface twist instabilities and skyrmion states in chiral ferromagnets
• Symmetry breaking, slow relaxation dynamics, and topological defects at the field-induced helix reorientation in MnSi
• Atomic scale visualization of topological spin textures in the chiral magnet MnGe
• Short period magnetization texture of B20-MnGe explained by thermally fluctuating local moments
• Hidden quantum phase transition in Mn${}_{1-x}$Fe${}_x$Ge: evidence brought by small-angle neutron scattering
• Molecular Beam Epitaxy Growth of [CrGe/MnGe/FeGe] Superlattices: Toward Artificial B20 Skyrmion Materials with Tunable Interactions
• Strain in epitaxial MnSi films on Si(111) in the thick film limit studied by polarization-dependent extended x-ray absorption fine structure
• Magnetic structure of the MnGe helimagnet and representation analysis
• Enhanced Electrical Magnetochiral Effect by Spin-hedgehog Lattice Structural Transition
• Stability of in-plane and out-of-plane chiral skyrmions in epitaxial MnSi(111)/Si(111) thin films: surface twists versus easy-plane anisotropy
• Topological magnetic structures in MnGe: Neutron diffraction and symmetry analysis