Nanogranular L1(0) FePt-C-Ta2O5 composite media for perpendicular recording applications

Area of Science:

• Materials Science
• Nanotechnology
• Physics

Background:

• FePt nanoparticles are promising for high-density magnetic recording media due to their high magnetocrystalline anisotropy.
• Controlling the magnetic properties and thermal stability of FePt films is crucial for device applications.
• Simultaneous doping strategies are explored to optimize FePt performance.

Purpose of the Study:

• To investigate the effects of co-doping with Carbon (C) and Tantalum Pentoxide (Ta2O5) on the magnetic properties of FePt films.
• To determine the influence of sputtering power on the microstructure and magnetic behavior of these doped films.
• To assess the retention of perpendicular magnetic anisotropy with increasing dopant concentrations.

Main Methods:

• Fabrication of (Fe55Pt45)79C21-(x vol%) Ta2O5 films (x = 0-20%) using magnetron sputtering at low and high powers.
• In-situ heating at 350°C on MgO/CrRu underlayers.
• Characterization using X-ray diffraction (XRD) and measurement of magnetic properties like out-of-plane coercivity and exchange coupling.

Main Results:

• Low-power sputtering: Decreased exchange coupling with increasing Ta2O5 content; maintained out-of-plane coercivity up to 7.2 kOe and FePt(001) texture.
• High-power sputtering: Initial increase in coercivity to 8.2 kOe and reduced exchange coupling (loop slope parameter approaching 1).
• Further doping at high power led to decreased coercivity and increased exchange coupling.

Conclusions:

• Simultaneous C and Ta2O5 doping effectively maintains perpendicular anisotropy in FePt films up to 20 vol% Ta2O5.
• Sputtering power significantly influences the magnetic properties and microstructure of the doped FePt films.
• These findings suggest potential for developing advanced magnetic storage media with optimized doping strategies.