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Gilbert damping in epitaxial Heusler Co2FeAl films with thickness varying from 3 nm to 9 nm are investigated by broadband ferromagnetic resonance (FMR) with a temperature range of 5 K to 300 K. Gilbert damping shows a continuous decrease with the increasing thickness of Co2FeAl films. Moreover, an enhanced peak of the Gilbert damping is observed with increasing temperature up to approximately 50 K for 3 nm,6 nm and 9 nm−thick Co2FeAl films, which may be attributed to the spin reorientation transition at Co2FeAl /MgO interface. Further, we analyzed the linewidth with a superposition of a uniaxial and a fourfold anisotropy for all samples, which suggests that FMR linewidth in epitaxial Co2FeAl films stems from two-magnon scattering. The change of Gilbert damping is confirmed to originate from various order degrees of the B2 phase with the growth of CFA film, impacting the control of magnetic damping in spin-based nanodevices.

Herein, we demonstrated an apparent electric field control of magnetization reorientation at room temperature, through a strain-mediated magnetoelectric coupling in ferromagnetic/ferroelectric (FM/FE) multiferroic heterostructure. As the applied electric field increased, the magnetization tended to deviate from the original direction, which was induced by nonlinear strain vs electric-field behavior from the ferroelectric substrates. Ferromagnetic resonance showed that the in-plane magnetic easy axis of the Co film was shifted sharply with electric field E = 10 kV/cm, which indicates that the in-plane uniaxial magnetic anisotropy of the Co film can be inverted via the application of an electric field. These results demonstrated that converse magnetoelectric effect in the FM/FE heterostructure was indeed a feasible method to control magnetization orientation in technologically relevant ferromagnetic thin films at room temperature.