Strain engineered domain structure and their relaxation in perpendicularly magnetized Co/Pt deposited on flexible polyimide

Abstract

The demand of fast and power efficient spintronic devices with flexibility requires additional energy for magnetization manipulation. Stress/ strain have shown their potentials for tuning magnetic properties to the desired level. Here, we report a systematic study for the effect of both tensile and compressive stresses on the magnetic anisotropy (MA). Further the effect of stress on the domain structure and magnetization relaxation mechanism in a perpendicularly magnetized Co/Pt film has been studied. It is observed that a minimal in-plane tensile strain has increased the coercivity of the film by 33% of its initial value, while a very small change of coercivity has been found under compressive strain. The size of ferromagnetic domains decreases under tensile strain, while no change is observed under the compressive strain. Magnetization relaxation measured at sub-coercive field values yields a longer relaxation time in the strained state. OPEN ACCESS RECEIVED

Enhanced Stress Stability in Flexible Co/Pt Multilayers with Strong Perpendicular Magnetic Anisotropy

“…The stress-invariant magnetic domains are consistent with the hysteresis loop measured by MOKE under different tensile strains (Figure S14). In addition, as the coercivity field shifts upon external stress, the domain nucleation and domain wall movement will be affected, as has been demonstrated by Pandey et al On the other hand, when t increases to 1.5 nm, the PMA weakens and magnetic domains become unstable against external stress, as is observed from the evolution of magnetic domains presented in Figure c. When the stress is released, the magnetic domains largely recover back to their initial state (Figure S15).…”

“…In recent years, magnetic materials with perpendicular magnetic anisotropy (PMA) have received considerable attention due to their potential in constructing magneto-electronic devices with low energy consumption and high thermal stability, such as the spin–orbit torque (SOT)-based 3D magnetic field sensors, magnetic memory, and logic devices. − There have been some reports on the stress tuning of PMA in flexible magnetic films. − For example, a reversible switching of the magnetic easy axis from in-plane (IP) to out-of-plane (OP) upon stretching the Co films has been revealed. , In a perpendicular magnetized CoFeB film, a switch from OP to IP magnetic anisotropy was observed with biaxial tensile stress . Until now, finding a strategy to enhance the stress stability of PMA in flexible magnetic films remains unresolved.…”

Magnetic properties of FeGa/Kapton for flexible electronics

“…Stress tunability in these materials is relatively low due to rigid substrates. Similar magneto-mechanical coupling effect was also studied on FeTaN 34 , FeZrN 35 , 36 , Co 37 and Co/Pt 38 thin films deposited on flexible substrates. However, FeGa possesses a much higher magnetostrictive constant as compared to other magnetic materials and hence it is promising for the design of flexible devices and stretchable electronics.…”