Magnetic Properties of Percolated Perpendicular FePt–MgO Films

Author

Sun, An-Cheng ; Hsu, Jen-Hwa ; Kuo, P.C. ; Huang, H.L.

Author_Institution

Dept. of Phys., Nat. Taiwan Univ., Taipei

Volume

43

Issue

6

fYear

2007

fDate

6/1/2007 12:00:00 AM

Firstpage

2130

Lastpage

2132

Abstract

Percolated perpendicular FePt-MgO films with a (Fe₄₈ Pt ₅₂)_100-x-(MgO)_x/Pt(001)/Cr(002) structure were prepared by conventional dc magnetron sputtering (x=0-6.13). Magnetic measurements demonstrate that the coercivity of the magnetic film drastically increases from 169 to 285 kA/m as the MgO content is increased from 0 to 0.15 vol.%. However, the grain sizes of the FePt phase do not significantly varying upon doping with MgO. MgO does not appear at the grain boundaries of the FePt phase, but is present as crystalline dots that are uniformly precipitated in the FePt matrix. The MFM images revealed that the domain structure transformed from extending to isolate when the MgO dots precipitated into the FePt grains. Consequently, the MgO dots serve as pinning sites of the domain wall and enhance perpendicular coercivity. Percolated perpendicular magnetic recording is thus regarded as a solution to the problem of thermal instability in ultrasmall grains

Keywords

chromium; coercive force; doping; ferromagnetic materials; grain boundaries; grain size; iron alloys; magnesium compounds; magnetic domain walls; magnetic force microscopy; magnetic multilayers; magnetic thin films; percolation; perpendicular magnetic recording; platinum; platinum alloys; (Fe₄₈Pt₅₂)_100-x-MgO-Pt-Cr; MFM; crystalline dots; dc magnetron sputtering; domain structure; domain wall pinning sites; doping; grain boundaries; grain size; magnetic films; magnetic properties; percolated perpendicular magnetic recording; perpendicular coercivity; thermal instability; Coercive force; Doping; Grain boundaries; Grain size; Iron; Magnetic films; Magnetic properties; Magnetic variables measurement; Perpendicular magnetic recording; Sputtering; Coercive force; FePt alloy; percolated meida; perpendicular magnetic recording; precipitation;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/TMAG.2007.892999

Filename

4202931