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.

Control of chiral magnetic domain walls in a Pt/CoFeB/Ir multilayer using ferroelectric BaTiO3 domains

“…However, to operate any of these devices in an energy-efficient manner, it is increasingly recognised that alternatives to magnetic field or electric current must be used. Magnetoelectric methods that use electric field to modify exchange coupling or magnetic anisotropy have been demonstrated to control domain walls, and are considered to be low-energy due to the lack of current flow and therefore minimal Joule heating [6,7,8]. Strain applied via a voltage-controlled piezoelectric, for example, modifies the magnetic anisotropy and has the advantage of allowing reversible control of magnetic properties of a multilayer with PMA, including domain wall dynamics [9].…”

Direct‐Current Electrical Detection of Surface‐Acoustic‐Wave‐Driven Ferromagnetic Resonance

“…As a result, SAW-driven FMR is at the heart of the acoustic control of magnetism and spin current, [4][5][6] including SAW-induced magnetization switching, [7][8][9] SAW-assisted spin-transfer torque, [10,11] and spin-orbit torque switching, [12] SAW-controlled spin texture creation and motion. [13][14][15][16][17][18] Meanwhile, integrating magnetism manipulation into SAW systems also provides a new approach for designing miniaturized RF devices such as isolators and circulators.…”

“…As a result, SAW‐driven FMR is at the heart of the acoustic control of magnetism and spin current, [ 4–6 ] including SAW‐induced magnetization switching, [ 7–9 ] SAW‐assisted spin‐transfer torque, [ 10,11 ] and spin‐orbit torque switching, [ 12 ] SAW‐controlled spin texture creation and motion. [ 13–18 ] Meanwhile, integrating magnetism manipulation into SAW systems also provides a new approach for designing miniaturized RF devices such as isolators and circulators. The key is to realize nonreciprocal SAW propagation, which can be achieved by the interference of shear‐ and longitudinal‐type magneto‐elastic couplings, [ 19–21 ] asymmetric spin wave dispersion via Dzyaloshinskii‐Moriya interaction [ 22,23 ] or ferromagnetic multilayers, [ 24–27 ] magneto‐rotation coupling, [ 28 ] and phonon angular momentum transfer.…”

Transport of skyrmions by surface acoustic waves

“…18 The dynamic strain induced by surface acoustic waves (SAWs) has also been suggested as an attractive approach to control thin film magnetization. [19][20][21][22][23][24][25][26][27][28][29][30][31] In particular, Yokouchi et al experimentally observed the creation of skyrmions by SAWs in a Pt/Co/Ir thin film owing to the inhomogeneous effective torque arising from both SAWs and thermal fluctuations via magnetoelastic coupling. 32 Nepal et al theoretically studied the dynamical pinning of skyrmion bubbles at the anti-nodes of standing SAWs in a FePt nano-wire, revealing the strain gradient induced by SAWs is the driving force for skyrmion motion.…”