Structure and magnetism of epitaxially strained Pd(001) films on Fe(001): Experiment and theory

Journal Article · Tue Feb 28 23:00:00 EST 1995 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.51.6364· OSTI ID:6459701

Fullerton, E E ^[1]; Stoeffler, D; Ounadjela, K ^[2]; Heinrich, B; Celinski, Z ^[3]; Bland, J A.C. ^[4]

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1. 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)
2. 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)
3. Physics Department, Simon Fraser University, Burnaby, British Columbia, V5A 1S6 (Canada)
4. 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), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 51:10; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
360104 -- Metals & Alloys-- Physical Properties
ANTIFERROMAGNETISM
COHERENT SCATTERING
CRYSTAL STRUCTURE
DIFFRACTION
ELEMENTS
EPITAXY
FERROMAGNETISM
FILMS
GOLD
INTERFACES
IRON
MAGNETISM
METALS
NEUTRON DIFFRACTION
PALLADIUM
PLATINUM METALS
SCATTERING
THIN FILMS
TRANSITION ELEMENTS
X-RAY DIFFRACTION