Electric-Field Modulation of Perpendicular Magnetic Anisotropy and Damping Constant in MgO/Co/Pt Trilayers

Electric field modulations of the perpendicular magnetic anisotropy (PMA) and magnetization dynamics of MgO/Co/Pt trilayers were measured by time-resolved magneto-optical Kerr effect (TRMOKE). The anisotropy field estimated from the anomalous Hall effect applying a field along in-plane was confirmed to be modified by the electric field, which results in the PMA variation with an electric field of -32 fJ/(V.m). The PMA variation was also confirmed from TRMOKE measurements, which was estimated to be -47 fJ/(V.m). From TRMOKE measurements, we also observed the reduction of the inverse of relaxation time 1/tau of the magnetization precession with increasing the electric field. The 1/tau was analyzed by assuming the contributions of effective Gilbert damping alpha(eff), anisotropy distribution, anisotropy angle distribution, and two magnon scattering, and we found alpha(eff) decreased with increasing the electric field whose modulation was -0.0046 nm/V, corresponding to -13% per 1 V/nm. These results are similar to the electric field effect in (001)-orientated MgO/CoFeB/Ta trilayers, however, our finding indicates similar PMA and alpha modulations are found in MgO/Co/Pt trilayers having MgO(111)/fcc-Co interface.

Automated summary

The electric field modulation of PMA and magnetization dynamics in MgO/Co/Pt trilayers was investigated using TRMOKE. The results showed that the PMA and α were both influenced by the electric field. Similar effects were observed in trilayers with MgO(111)/fcc-Co interface.