Current Control of Magnetic Anisotropy via Strain in a CoFeB Waveguide*

We demonstrate that in-plane charge current can effectively control the spin precession resonance in an Al$_{\mathrm{2}}$O$_{\mathrm{3}}$/CoFeB/Ta heterostructure. Brillouin Light Scattering (BLS) was used to detect the ferromagnetic resonance field under microwave excitation of spin waves at fixed frequencies. Such control originates from the modified in-plane uniaxial magnetic anisotropy field $H_{\mathrm{k}}$, which changes symmetrically with respect to the current direction. Numerical simulation suggests that the anisotropic stressintroduced by Joule heating plays an important role in controlling $H_{\mathrm{k}}$. The results provide new insights into current manipulation of magnetic properties and have broad implications on spintronic devices.