AVS 46th International Symposium
    Magnetic Interfaces and Nanostructures Technical Group Tuesday Sessions
       Session MI+VM+AS-TuM

Paper MI+VM+AS-TuM3
Ion Induced Magnetization Reorientation in Co/Pt Multilayers for Patterned Media

Tuesday, October 26, 1999, 9:00 am, Room 618/619

Session: Magnetic Recording: Media
Presenter: D. Weller, IBM Almaden Research Center
Authors: D. Weller, IBM Almaden Research Center
J.E.E. Baglin, IBM Almaden Research Center
K.A. Hannibal, IBM Almaden Research Center
M.F. Toney, IBM Almaden Research Center
L. Folks, IBM Almaden Research Center
A.J. Kellock, IBM Almaden Research Center
M.E. Best, IBM Almaden Research Center
B.D. Terris, IBM Almaden Research Center
Correspondent: Click to Email
Ion beam patterning of magnetic thin films using stencil masks is a prospective path towards ultrahigh-density magnetic recording media. Co/Pt multilayers are ideally suited for this application, since they undergo a spin-reorientation transition from easy axis out-of-plane to easy axis in-plane upon irradiation with ions of suitable energy and dose.@footnote 1@ The mechanism, leading to the observed modulation in magnetic properties is of great fundamental and technological interest and will be discussed in this paper. Electron beam deposited Co/Pt multilayers with representative structure [Si-substrate/SiNx/20 nm Pt buffer/10x(0.3nm Co/1 nm Pt)/2 nm Pt cap layer] were used. These structures have high coercivity (H@sub C@ = 5000- 8500 Oe) and exhibit square perpendicular hysteresis. The high coercivity is attributed to the the large perpendicular anisotropy (K@sub u@ = 4.3 10@super 7@ erg/cm@super 3@) and granularity of these films as indicated in AFM surface topography measurements. The structures were subjected to various doses and currents of 700 keV N@super +@ ions and investigated after each irradiation step using grazing incidence X-ray reflectivity and Kerr hysteresis loop measurements. Direct evidence for ion beam mixing at the Co/Pt interface is found from the XRD data. In particular, we find an almost linear decrease of the integrated intensity of the first grazing incidence Bragg peak with ion dose. This correlates with the measured remanence ratio and anisotropy, however, not with the coercivity, which drops off much faster. @FootnoteText@ @footnote 1@ C. Chappert et al., Science 280, 1919 (1998).