Local anisotropy control of Pt/Co/Ir thin film with perpendicular magnetic anisotropy by surface acoustic waves

Abstract

The control of perpendicular magnetic anisotropy (PMA) in thin films by strain has considerable potential for energy-efficient information storage and data processing. Here, we report on the control of PMA in Pt/Co/Ir thin films by the strain produced by standing surface acoustic waves (SAWs). A significant (∼21%) coercivity reduction (from 4.80 ± 0.03 to 3.80 ± 0.02 mT) can be obtained by applying a standing SAW with a center frequency of 93.35 MHz. Furthermore, the standing SAWs induce a greater-than 11-fold increase in magnetization reversal speed (from 168 ± 3 to up to 2100 ± 80 μm2/s) at 3.2 mT for a total applied RF power of 22.5 dBm. During application of SAWs, wide-field Kerr microscopy reveals the formation of domains in stripes with a periodicity of half of the SAW wavelength. Micromagnetic simulations indicate that the anti-nodes of the standing SAW locally lower the anisotropy due to the magneto-elastic coupling effect, decreasing domain nucleation field while promoting magnetization reversal. Our study suggests the possibility of remote and energy-efficient control of magnetization switching using SAWs.