Large perpendicular magnetic anisotropy in magnetostrictive Fe(1-x)Gax thin films

M.BARTUREN; J.MILANO; M.VASQUEZ-MANSILLA; C.HELMAN; M.A. BARRAL; M.EDDRIEF; M.MARANGOLO; ANA MARÍA LLOIS

PHYSICAL REVIEW B

AMER PHYSICAL SOC

Lugar: New York; Año: 2015 vol. 92 p. 544181 - 544186

1098-0121

In this work we report the appearance of a large perpendicular magnetic anisotropy (PMA) in Fe1−xGax thin films grown onto ZnSe/GaAs(001). This arising anisotropy is related to the tetragonal metastable phase in as-grown samples recently reported [M. Eddrief et al., Phys. Rev. B 84, 161410 (2011)]. By means of ferromagnetic resonance studies we measured PMA values up to ∼5 × 105 J/m3. PMA vanishes when the cubic structure is recovered upon annealing at 300 ◦C. Despite the important values of the magnetoelastic constantsmeasured via the cantilever method, the consequent magnetoelastic contribution to PMA is not enough to explain the observed anisotropy values in the distorted state. Ab initio calculations show that the chemical ordering plays a crucial role in the appearance of PMA. Through a phenomenological model we propose that an excess ofnext-nearest-neighbor Ga pairs (B2-like ordering) along the perpendicular direction arises as a possible source of PMA in Fe1−xGax thin films.