Enhanced interlayer Dzyaloshinskii–Moriya interaction and field-free switching in magnetic trilayers with orthogonal magnetization

Abstract

The indirect interlayer exchange coupling (IEC) between two magnetic layers holds significant importance in the field of spintronics and has been widely used in the construction of synthetic antiferromagnets. Recently, the interlayer Dzyaloshinskii–Moriya interaction (DMI), antisymmetric counterpart of IEC, has been discovered in magnetic trilayers with a heavy-metal spacer. In this study, we present an investigation on antisymmetric and symmetric counterparts of IEC in D022-Mn3Ga/Pt/Co trilayers with orthogonal magnetization. Due to the strong interlayer DMI across the entire multilayer, the symmetry of magnetic reversal process was broken, leading to an enhanced chiral exchange-bias field of 42.7 Oe in the Co layer. In addition, field-free spin–orbit torque (SOT) switching of D022-Mn3Ga layer has been realized in Hall bar devices. In-plane field dependence analysis of the SOT switching behavior reveals that the symmetric counterpart of IEC exhibits antiferromagnetic characteristics within the spacer thickness range of 2 nm ≤ tPt ≤5 nm. Moreover, the magnitude of both antisymmetric and symmetric counterparts of IEC exhibits an exponential decreasing trend with increasing tPt. These findings hold significant implications for the design and manipulation of three-dimensional chiral spin textures in the future spintronic devices.