Magnetization reversal and domain structures in perpendicular synthetic antiferromagnets prepared on rigid and flexible substrates

TL;DR

This study investigates magnetization reversal and domain structures in synthetic antiferromagnets with varying spacer layer thicknesses on rigid and flexible substrates, highlighting strain effects on interlayer coupling for flexible spintronics.

Contribution

It demonstrates how spacer layer thickness and substrate flexibility influence magnetic coupling and reversal, introducing strain as a tuning parameter for SAF properties.

Findings

FM and AFM coupling depend on Ir spacer thickness

Strain modifies interlayer exchange coupling

Flexible substrates enable strain-controlled magnetic behavior

Abstract

Ferromagnetic (FM) layers separated by nonmagnetic metallic spacer layers can exhibit Ruderman Kittel Kasuya Yosida (RKKY) coupling which may lead to a stable synthetic antiferromagnetic (SAF) phase. In this article we study magnetization reversal in [Co/Pt] layers by varying the number of bilayer stacks (Pt/Co) as well as thickness of Ir space layer tIr on rigid Si(100) and flexible polyimide substrates. The samples with tIr = 1.0 nm shows a FM coupling whereas samples with tIr = 1.5 nm shows an AFM coupling between the FM layers. At tIr = 2.0 nm, it shows a bow-tie shaped hysteresis loop indicating a canting of magnetization at the reversal. Higher anisotropy energy as compared to the interlayer exchange coupling (IEC) energy is an indication of the smaller relative angle between the magnetization of lower and upper FM layers. We have also demonstrated the strain induced modification of IEC as well as magnetization reversal phenomena. The IEC shows a slight decrease upon application of compressive strain and increase upon application of tensile strain which indicates the potential of SAFs in flexible spintronics.