Tailoring the magnetism and spin dynamics in CoFeB thin films by post annealing for spintronics applications

Soft magnetic CoFeB thin films have received remarkable interests in spintronics due to its appealing magnetic and electronic properties. The microstructural, static and the dynamic magnetic properties of CoFeB thin films prepared by oblique deposition technique and annealed at different temperatures are systematically investigated, to manipulate and optimize its magnetism such as exchange constant A, saturation magnetization Ms and the magnetic Gilbert damping constant α for spintonics application. It has been shown experimentally that both the in-plane uniaxial magnetic anisotropy field Hk and the value of Gilbert damping α decreases with increasing annealing temperature, in contrast to the increasing tendency of exchange constant A. The above behavior might be due to the crystallization and degradation of oblique deposition induced columnar grains in the annealing treatment. Moreover, the annealing effect on the product of α and Ms (αMs) is also revealed, showing a decreasing trend with the increasing annealing temperature which suggest a promising application prospect of the annealed CoFeB thin film in magnetic storage devices such as STT-MRAM.