Significant Reorientation Transition of Magnetic Damping Anisotropy in Co2FeAl Heusler Alloy Films at Low Temperatures

The temperature (T) dependences of magnetization dynamics, especially for magnetic damping anisotropy, have been systematically investigated in well-ordered Co2FeAl films with a biaxial anisotropy. It is found that the damping anisotropy factor Q, defined as the fractional difference of damping between the hard and easy axes, changes from 0.35 to -0.09 as T decreases from 300 to 80 K, performing a distinctive reorientation transition at T similar to 200 K. Through the thickness-dependent damping measurement results, the damping anisotropy reorientation is verified to originate from the competitions between the intrinsic anisotropic distribution of bulk spin orbit coupling and the interfacial two-magnon scattering. The former governs the effective damping at high temperatures, while the latter with an opposite fourfold symmetry gradually plays a dominant role at reduced temperatures, leading to the transition of the Q value from positive to negative. The clear clarification of damping anisotropy variation as well as the underlying mechanism in this study would be of great importance for designing key spintronic devices with optimized dynamic magnetic properties.

Automated summary

This study systematically investigates the temperature dependence of magnetization dynamics, particularly the magnetic damping anisotropy. It is found that the damping anisotropy undergoes a distinctive reorientation transition at around 200K as the temperature decreases. The competition between the intrinsic anisotropic distribution of bulk spin orbit coupling and the interfacial two-magnon scattering plays a crucial role in this reorientation. This research provides a clear understanding of damping anisotropy variation and the underlying mechanism, which is of great importance for designing spintronic devices with optimized dynamic magnetic properties.