Layered structure and related magnetic properties for annealed Fe/Ir(111) ultrathin films

After annealing treatments for fcc-Fe/Ir(111) below 600 K, the surface layers remain pseudomorphic. The Ir(111) substrate plays an important role on the expanded Fe lattice. At temperatures between 750 and 800 K, the surface composition shows a stable state and a c(2 × 4) structure is observed. We d...

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Bibliographic Details
Published inJournal of applied physics Vol. 117; no. 17
Main Authors Jiang, Pei-Cheng, Chen, Wei-Hsiang, Hsieh, Chen-Yuan, Tsay, Jyh-Shen
Format Journal Article
LanguageEnglish
Published Melville American Institute of Physics 07.05.2015
Subjects
ANNEALING
BCC LATTICES
CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
FCC LATTICES
Ferromagnetism
FORMATION HEAT
FREE ENERGY
INTERFACES
IRIDIUM
IRON
LAYERS
MAGNETIC PROPERTIES
STRAINS
SUBSTRATES
Surface layers
SURFACES
TEMPERATURE DEPENDENCE
THIN FILMS
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Summary:After annealing treatments for fcc-Fe/Ir(111) below 600 K, the surface layers remain pseudomorphic. The Ir(111) substrate plays an important role on the expanded Fe lattice. At temperatures between 750 and 800 K, the surface composition shows a stable state and a c(2 × 4) structure is observed. We discover a layered structure composed of some Fe atoms on the top of a Fe0.5Ir0.5 interfacial alloy supported on the Ir(111) substrate. The competition between the negative formation heat of Fe0.5Ir0.5 and surface free energy of Fe causes the formation of layered structure. The existence of ferromagnetic dead layer coincides with the formation of fcc-Fe for ultrathin Fe on Fe0.5Ir0.5/Ir(111). For Fe films thicker than three monolayers, the linear increase of the Kerr intensity versus the Fe coverage is related to the growing of bcc-Fe on the surface where the Fe layer is incoherent to the underlying Fe0.5Ir0.5/Ir(111). These results emphasize the importance of the substrate induced strain and layered structure of Fe/Fe0.5Ir0.5/Ir(111) on the magnetic properties and provide valuable information for future applications.
ISSN:0021-8979
1089-7550
DOI:10.1063/1.4919123