Nanogranular L1 0 FePt-C-Ta 2O 5 composite media for perpendicular recording applications

Abstract

In this report, the effect of simultaneously adding two dopants (C and Ta 2O 5) in FePt was investigated. (Fe 55Pt 45) 79C 21-(x vol%) Ta 2O 5 films (where x = 0% to 20%) were prepared using both low and high power magnetron sputtering on MgO (2 nm)/CrRu (30 nm) underlayers with in-situ heating at 350 °C. Films deposited at low power showed a dercrease in exchange coupling with increasing Ta 2O 5 content. Out-of-plane coercivity of 7.2 kOe was observed even with up to 20 vol% Ta 2O 5. X-Ray diffraction spectra showed presence of FePt(001) texture for all compositions of Ta 2O 5 ranging from 0 to 20 vol% suggesting tha t the per pendicular anisotropy was maintained even with up to 20 vol% of dopant content. Films deposited at high power showed a different behavior with an initial increase in out-of-plane coercivity to 8.2 kOe and a reduction in exchange coupling with loop slope parameter (α) approaching a fully decoupled value of 1. Further increase in doping content led to deterioration in the out-of-plane coercivity, as well as an increase in the exchange coupling. © 2011 American Scientific Publishers.