Structural and magnetic properties of Co2FeGa full-Heusler alloy thin films with low Gilbert damping

Highly ordered Co2FeGa thin films were successfully prepared using direct current magnetron sputtering by adjusting the film growth conditions. This involved making modifications to substrate and annealing temperatures. Structural, chemical, and magnetic properties were systematically studied using global and surface techniques. The results showed a transition from a partially ordered film grown at 300 degrees C to a highly ordered L21 fullHeusler phase at 600 degrees C. X-ray photoelectron spectroscopy confirmed a stoichiometric Co2FeGa alloy for the films, while 57 Fe conversion electron Mo<spacing diaeresis>ssbauer spectroscopy revealed the atomic disorder-order transition induced by high substrate temperatures and/or annealing temperatures. The magnetic properties were found to be strongly influenced by the thermal history of the films. Saturation magnetization reached 1200 kA/m and coercivity was as low as 0.8 mT for the film growth at 600 degrees C. Ferromagnetic resonance showed that the alpha-Gilbert damping parameter was significantly affected by growth conditions with a value of 0.0015(3) measured in films grown at the highest temperature. This study demonstrates that precise control over film crystallinity and atomic ordering can lead to low alpha-damping values in polycrystalline Co2FeGa thin films, making them promising materials for use in spintronic devices.