Ultrafast demagnetization and Gilbert damping in electrodeposited CoP film

From portable electronics to high-performance computing, the requirement for miniaturized and high-efficiency power supply is ever-increasing. Soft magnetic material with higher resistivity and moderate anisotropy field can be considered as a promising candidate as core materials for high-frequency integrated magnetic passives leading to such on-chip power supply devices. Here, in-plane magnetic orientation (φ)dependent ultrafast magnetization dynamics of electrodeposited cobalt phosphorus (CoP) alloy are investigated with partial demagnetization within few hundreds of femtoseconds (fs) followed by fast and slow relaxation in relatively longer timescale. The precession frequency extracted from the magnetization precession shows dominant two-fold anisotropy superposed with a moderate four-fold anisotropy, whereas the Gilbert damping coefficient reveals a four-fold anisotropy as a function of φ . On the contrary, the ultrafast demagnetization is found to be nearly isotropic with φ . We can speculate that spin–orbit coupling (SOC) plays a major role in these anisotropic precessional dynamics but for highly non-equilibrium dynamics, the role of anisotropic SOC is negligible for ultrafast spin-flip scattering process. Such detailed studies of ultrafast spin dynamics revealing important dynamical properties will underpin potential applications in high-frequency integrated magnetic passives for future monolithic power supply on-chip. Graphical abstract: [Figure not available: see fulltext.]