Magnetization dynamics and interface studies in ion-beam sputtered Si/CoFeB(8)/MgO(4)/CoFeB(8)/Ta(5) structures

摘要

The interface roughness, Boron distribution in bulk CoFeB and at interface, Gilbert damping constant (α), and inhomogeneous broadening in ion-beam sputtered Si/CoFeB(8)/MgO(4)/ CoFeB(8)/Ta(5) structures are found to be sensitive to the MgO growth process. The ion-assist and reactive growth processes that result in sharper interfaces of width ～0.5 nm lead to smaller a of 0.0050 ± 0.0003 and 0.0060 ± 0.0002 and inhomogeneous broadening ΔH_0 of 3 ± 0.3 and 1 ± 0.3 Oe, respectively. On the other hand, the post-oxidation method results in rough interface and higher retention of Boron in CoFeB leading to higher values for a and ΔH_0 as 0.0080 ± 0.0006 and 5 ± 0.3 Oe, respectively.