FERROMAGNETIC DELTA-MN1-XGAX THIN-FILMS WITH PERPENDICULAR ANISOTROPY

We report the structure and properties of the thermodynamically stable delta-phase Mn1-xGax single crystal thin films grown on GaAs. X-ray THETA-2THETA scans and grazing-incidence scattering measurements confirmed that the unit cell of this phase is tetragonal (a = 0.279 nm, c = 0.351 nm) and grows with the c-axis oriented normal to the {001} GaAs substrate surface. X-ray emission spectroscopy confirmed the composition to be 62 +/- 2% Mn. Polar Kerr rotation, SQUID and vibrating sample magnetometer measurements with the field applied along the thin-film normal showed nearly perfect square hysteresis loops confirming perpendicular anisotropy of the films. The film exhibits a Kerr rotation angle of approximately 0.1-degrees at 820 nm, a coercivity of 6.27 kOe and a saturation magnetization of 460 emu/cm3. The optical reflectivity of the film was 65%-70% over a broad range of wavelengths. This unique set of properties make it a very promising material for magneto-optic recording with the additional potential of integrating semiconductor/magnetic devices by suitable patterning techniques.