Structure and magnetism of epitaxially strained Pd(001) films on Fe(001): Experiment and theory
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States) Department of Physics, University of California-San Diego, La Jolla, California 92093 (United States)
- Institut de Physique et de Chimie des Materiaux de Strasbourg- (U.M.R. 46 C.N.R.S.), 23 rue du Loess, 67037 Strasbourg (France)
- Physics Department, Simon Fraser University, Burnaby, British Columbia, V5A 1S6 (Canada)
- Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom)
We present an experimental and theoretical description of the structure and magnetism of epitaxially strained Pd(001) films on Fe(001) and in Fe/Pd/Fe(001) trilayers. The structure is determined by combining reflection high-energy electron diffraction and x-ray diffraction. For Fe/Au(001) bilayers and Fe/Pd/Au(001) trilayers grown by molecular-beam epitaxy on Ag(001), the Fe and Au layers are well represented by their bulk structure, whereas, thin Pd layers have a face-centered tetragonal structure with an in-plane expansion of 4.2% and an out-of-plane contraction of 7.2% ([ital c]/[ital a]=0.89). Theoretical [ital ab] [ital initio] studies of the interfacial structure indicate that the structural ground state of the epitaxially strained Pd layer is well described by a fct structure which maintains the bulk Pd atomic volume with small deviations at the interface. For Fe/Pd/Fe trilayers, the interlayer coupling oscillates with a period of 4 monolayers (ML) on a ferromagnetic background that crosses to weak antiferromagnetic coupling for thicknesses [gt]12 ML of Pd. Strong ferromagnetic coupling observed below 5 ML of Pd indicates that 2 ML of Pd at each interface are ferromagnetically ordered. Theoretical studies of Fe[sub 3]Pd[sub [ital n]] superlattices (where [ital n] is the number of Pd atomic layers) determine the polarization of the Pd layer and the interlayer magnetic coupling to depend strongly on the [ital c]/[ital a] ratio of the Pd layers. Modeling of a Pd layer with a constant-volume fct structure and one monolayer interfacial roughness find that the first 2 ML of the Pd is polarized in close agreement with the experimental results. Polarized neutron reflectivity results on an Fe(5.6 ML)/Pd(7 ML)/Au(20 ML) sample determine the average moment per Fe atom of 2.66[plus minus]0.05[mu][sub [ital B]]. Calculations for the same structure show that this value is consistent with the induced Pd polarization.
- Research Organization:
- Argonne National Laboratory (ANL), Argonne, IL
- DOE Contract Number:
- W-31109-ENG-38; FG03-87ER45332
- OSTI ID:
- 6459701
- Journal Information:
- Physical Review, B: Condensed Matter; (United States), Vol. 51:10; ISSN 0163-1829
- Country of Publication:
- United States
- Language:
- English
Similar Records
Magnetic properties of Fe films and Fe/Si/Fe trilayers grown on GaAs(001) and MgO(001) by ion-beam sputter epitaxy
Low-energy electron diffraction structure studies of thin films of Fe on W(001) and of oxygen-exposed thin films of Fe on Ag(001)
Related Subjects
IRON
INTERFACES
PALLADIUM
EPITAXY
ANTIFERROMAGNETISM
CRYSTAL STRUCTURE
FERROMAGNETISM
GOLD
NEUTRON DIFFRACTION
THIN FILMS
X-RAY DIFFRACTION
COHERENT SCATTERING
DIFFRACTION
ELEMENTS
FILMS
MAGNETISM
METALS
PLATINUM METALS
SCATTERING
TRANSITION ELEMENTS
360102* - Metals & Alloys- Structure & Phase Studies
360104 - Metals & Alloys- Physical Properties