TY - JOUR
T1 - Ab initio investigation of the magnetism of tetragonal Mn: Bulk, surface, ultrathin films, and multilayers
AU - Hafner, Juergen
AU - Spisak, Daniel
N1 - Zeitschrift: Physical Review B - Condensed Matter and Materials Physics
DOI: 10.1103/PhysRevB.72.144420
Coden: PRBMD
Affiliations: Institut für Materialphysik, Center for Computational Materials Science, Universität Wien, Sensengasse 8, A-1090 Wien, Austria
Adressen: Hafner, J.; Institut für Materialphysik; Center for Computational Materials Science; Universität Wien; Sensengasse 8 A-1090 Wien, Austria; email: [email protected]
Import aus Scopus: 2-s2.0-29744468612
22.10.2007: Datenanforderung 1935 (Import Sachbearbeiter)
22.10.2007: Datenanforderung 1936 (Import Sachbearbeiter)
PY - 2005
Y1 - 2005
N2 - The magnetic properties of the tetragonally distorted ? and ? phases of Mn stabilized by epitaxial growth on metallic surfaces are still subject of a lively debate, but so far no consistent and generally accepted picture has emerged. We have performed detailed and comprehensive investigations of the geometric and magnetic properties of tetragonal Mn in the bulk, at a (100) surface, in ultrathin MnFe(100) films, and in MnFe multilayers using ab initio spin-density functional techniques. The cubic structures of both ? (face-centered cubic) and ? (body-centered cubic) Mn are unstable against tetragonal distortion. Whereas for ?-Mn a structure contracted along the c axis and with c(2×2) in-plane (100) antiferromagnetism (AFM) is the unique ground state, for ?-Mn a contracted tetragonal (c a=0.945) phase with a layered (100) AFM, and an expanded (c a=1.048) phase with in-plane (100) AFM are energetically almost degenerate. In addition we find that the antiferromagnetic phases of both ? and ? Mn are susceptible to long-period helical modulations. At the (100) surface, the Mn moments are strongly enhanced, and the strong antiferromagnetic coupling between the high surface moments favors in-plane AFM in the surface layer even on top of the tetragonally compressed near-fcc phase stabilizing layered antiferromagnetism in the bulk. A similar result is found for ultrathin MnFe(100) films with up to six monolayers. A strong ferromagnetic MnFe coupling at the interface favors layered antiferromagnetism in the deeper layers, but the in-plane antiferromagnetic structure in the top layer is stable in any case. For the thinnest Mn films we have also examined noncollinear magnetic structures and found evidence for a perpendicular coupling between the Mn surface layer and the deeper layers of film and substrate. The strong ferromagnetic MnFe interface coupling also determines the properties of FeMn multilayers. The ferromagnetic interface coupling is not perturbed by FeMn intermixing and stabilizes a layered antiferromagnetism in the Mn spacer. We discuss our results in the light of the available experimental data and of previous theoretical calculations. Œ 2005 The American Physical Society.
AB - The magnetic properties of the tetragonally distorted ? and ? phases of Mn stabilized by epitaxial growth on metallic surfaces are still subject of a lively debate, but so far no consistent and generally accepted picture has emerged. We have performed detailed and comprehensive investigations of the geometric and magnetic properties of tetragonal Mn in the bulk, at a (100) surface, in ultrathin MnFe(100) films, and in MnFe multilayers using ab initio spin-density functional techniques. The cubic structures of both ? (face-centered cubic) and ? (body-centered cubic) Mn are unstable against tetragonal distortion. Whereas for ?-Mn a structure contracted along the c axis and with c(2×2) in-plane (100) antiferromagnetism (AFM) is the unique ground state, for ?-Mn a contracted tetragonal (c a=0.945) phase with a layered (100) AFM, and an expanded (c a=1.048) phase with in-plane (100) AFM are energetically almost degenerate. In addition we find that the antiferromagnetic phases of both ? and ? Mn are susceptible to long-period helical modulations. At the (100) surface, the Mn moments are strongly enhanced, and the strong antiferromagnetic coupling between the high surface moments favors in-plane AFM in the surface layer even on top of the tetragonally compressed near-fcc phase stabilizing layered antiferromagnetism in the bulk. A similar result is found for ultrathin MnFe(100) films with up to six monolayers. A strong ferromagnetic MnFe coupling at the interface favors layered antiferromagnetism in the deeper layers, but the in-plane antiferromagnetic structure in the top layer is stable in any case. For the thinnest Mn films we have also examined noncollinear magnetic structures and found evidence for a perpendicular coupling between the Mn surface layer and the deeper layers of film and substrate. The strong ferromagnetic MnFe interface coupling also determines the properties of FeMn multilayers. The ferromagnetic interface coupling is not perturbed by FeMn intermixing and stabilizes a layered antiferromagnetism in the Mn spacer. We discuss our results in the light of the available experimental data and of previous theoretical calculations. Œ 2005 The American Physical Society.
U2 - 10.1103/PhysRevB.72.144420
DO - 10.1103/PhysRevB.72.144420
M3 - Article
SN - 1098-0121
VL - 72
JO - Physical Review B
JF - Physical Review B
IS - 14
M1 - 144420
ER -