Title :
Magnetic Properties of Ultrathin Magnetite Films Grown by Molecular Beam Epitaxy
Author :
Arora, S.K. ; Wu, Han-Chun ; Yao, Hongzhi ; Ching, W.Y. ; Choudhary, R.J. ; Shvets, I.V. ; Mryasov, O.N.
Author_Institution :
Sch. of Phys., Centre for Res. on Adaptive Nanostruct. & Nanodevices, Trinity Coll. Dublin, Dublin
Abstract :
Magnetic properties as a function of film thickness (2-55 nm) for magnetite (Fe3O4) thin films grown on MgO (100) substrates show that the small thickness films (les 5 nm) are ferromagnetic and possess magnetization values which are much greater than that of bulk Fe3O4 . The inverse thickness dependence of the magnetization points to an interface related mechanism. Whereas, our detailed spin polarized density functional theoretical calculations suggests that there is only a marginal enhancement in the local spin moments of Fe-atom in the vicinity of the Fe3O4-MgO interface and it turns out that the noncompensation of spin moments between the two magnetic sublattices of spinel Fe3O4 is a major factor contributing to the enhancement of magnetization.
Keywords :
density functional theory; ferromagnetic materials; iron compounds; local moments; magnetic epitaxial layers; magnetisation; molecular beam epitaxial growth; Fe3O4; MgO; MgO (100) substrates; ferromagnetism; local spin moments; magnetic sublattices; magnetization; molecular beam epitaxy; size 2 nm to 55 nm; spin polarized density functional theoretical calculations; ultrathin magnetite films; Epitaxial layers; interface phenomena; magnetite; surfaces;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2008.2003173
