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Enhanced magnetic properties of annealed Fe 48 Pt 52 C composite films by N incorporation
Author(s) -
Mi W. B.,
Jin J.,
Bai H. L.
Publication year - 2011
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201026574
Subject(s) - coercivity , materials science , tetragonal crystal system , magnetization , annealing (glass) , sputtering , film plane , condensed matter physics , lattice (music) , analytical chemistry (journal) , magnetic anisotropy , magnetic field , composite material , crystallography , thin film , crystal structure , nanotechnology , chemistry , physics , chromatography , quantum mechanics , acoustics
N‐incorporated Fe 48 Pt 52 C composite films were fabricated using a reactive facing‐target sputtering system in a mixture of Ar and N 2 gases, and annealed in a chamber with the vacuum of 10 −6 Pa. Upon annealing, the escape of N atoms improves the ordering of the face‐centered tetragonal (fct) FePt grains. The coercivity of the 100‐nm thick films increases with the increase of nitrogen partial pressure. The maximum coercivity reaches 7.2 kOe at a 10‐kOe field, and the reversal mechanism approaches the Stoner–Wohlfarth (S–W) rotation mode. The easy axis turns from perpendicular to parallel to the film plane, and the coercivity increases with the increase of the film thickness ( t ). With increasing t , the out‐of‐plane magnetization decreases, but the in‐plane magnetization first increases, then decreases. The change of the magnetic properties should be related to the escape of the N atoms and the lattice mismatch effect of the MgO(100) substrates.