The interfacial Dzyaloshinskii–Moriya interaction (DMI) in ferromagnetic/non‐magnetic‐metal bilayers is essential to stabilize chiral spin textures for potential applications. Recent works reveal that the interlayer DMI is beneficial to designing 3D chiral spin textures that possess fundamental importance and the associated technological promises. Here, the interlayer DM constants are determined quantitatively in synthetic ferromagnetic/antiferromagnetic Pt/Co/Pt/Ru/Pt/Co/Ta structures. The results demonstrate that the interlayer DMI shows uniaxial anisotropic characteristics. The first‐principles calculations elucidate that the anisotropic interlayer DMI is induced by the in‐plane symmetry breaking along two high symmetric directions, which favors the magnetization of adjacent ferromagnetic layers canting in different directions. The anisotropic interlayer DMI is also confirmed by spin‐orbit torque driven asymmetric magnetization switching. Moreover, the interlayer DMI can be tuned by the Ru‐layer‐thickness and beneficial to designing 3D spin textures for future spintronic devices.

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In this paper, compact microwave components, including a Wilkinson power divider and a 3 dB branch-line coupler based on artificial transmission lines (ATLs) with harmonic suppression, are presented. A section ATL is consisted of microstrip stepped impedance transmission lines and a microstrip interdigital capacitor. To achieve a compact size, the stepped impedance transmission lines are folded into a right-angled triangle shape. For the ATL, the interdigital capacitor is used to suppress harmonics. By employing two sections of 70.7 Ω ATLs with a right-angled triangle shape to replace conventional transmission lines, the proposed power divider working at 0.9 GHz achieves a size miniaturization with the 58.8% area of a conventional case. In addition, the power divider has good harmonic suppression performance. In the design of a branch-line coupler, two pairs of ATLs with 50 Ω and 35.4 Ω are utilized. For 50 Ω ATLs, the ATLs are designed to a right-angled triangle shape. Meanwhile, to obtain a more compact size, these 35.4 Ω ATLs are modified to an isosceles trapezoid shape. The proposed branch-line coupler operating at 0.9 GHz accounts for merely 33.4% of a coupler adopting conventional microstrip transmission lines. Moreover, the harmonics of a branch-line coupler are suppressed effectively as well. Finally, measured results of the proposed Wilkinson power divider and branch-line coupler display good performance and agree with their simulated results well.

The spin-orbit torque via the spin Hall effect of heavy metals has shown promising prospect in driving the magnetization switching in spintronic devices due to the generated spin current from heavy metals. Recently, the 3d-light metals have been predicted the ability to generate orbital current and the associated orbital torques from the orbital Hall effect. However, few experiments have been carried out since it’s quite hard to directly detect the orbital current generated orbital torque. Here, we report an effective method to demonstrate the strong orbital torques in light metal Cr through a conversion process from orbital current to spin current by introducing the Pt interfacial layer in perpendicular magnetized symmetric Pt/Co/Pt structures. A quite large and monotonically growth of orbital torque efficiency in Pt/Co/Pt/Cr with the increase of the thickness of Cr layer is obtained with the largest effective orbital torque efficiency around 2.6 Oe/(MA·cm-2). The ability of orbital torque to drive the magnetization switching is also reported with the critical switching current density down to the order of 106 A·cm-2. Our findings prove the efficiency for switching the magnetization from light metal Cr layers through the orbital Hall effect.

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