Temperature dependence of the perpendicular magnetic anisotropy in Ta/Co2FeAl/MgO structures probed by Anomalous Hall Effect

• Perpendicular magnetic anisotropy (PMA) is achieved in ultrathin Co2FeAl thin films.
• Surface magnetic anisotropy shows an important increase with decreasing temperature.
• Bulk magnetic anisotropy becomes non-negligible at low temperatures.
• Surface magnetic anisotropy is the sole responsible for PMA.

We report a detailed study of the temperature dependence of the magnetic anisotropy in Ta/Co2FeAl/MgO structures by means of Anomalous Hall Effect measurements. The volume magnetic anisotropy, although negligible at room temperature, shows a non-negligible value at low temperatures and favors an in-plane easy magnetization axis. The surface magnetic anisotropy, which promotes the perpendicular magnetic easy axis, shows an increase from 0.76±0.05erg/cm2 at 300 K, up to 1.08±0.04erg/cm2 at 5 K, attributed to the evolution of the Co2FeAl layer saturation magnetization with temperature.