Science and Technology, NO-7491 Trondheim, Norway ‡ These two authors contribute equally to this work Keywords: Magnetic insulator, SOT switching, Dzyaloshinskii-Moriya interaction, Chiral domain wall, Skyrmion. The interfacial Dzyaloshinskii-Moriya interaction (DMI) in multilayers of heavy metal and ferromagnetic metals enables the stabilization of novel chiral spin structures such as skyrmions. Magnetic insulators, on the other hand can exhibit enhanced dynamics and properties such as lower magnetic damping and therefore it is of interest to combine the properties enabled by interfacial DMI with insulating systems. Here, we demonstrate the presence of interfacial DMI in heterostructures that include insulating magnetic layers. We use a bilayer of perpendicularly magnetized insulating thulium iron garnet (TmIG) and the heavy metal platinum, and find a surprisingly strong interfacial DMI that, combined with spin-orbit torque results, in efficient switching. The interfacial origin is confirmed through thickness dependence measurements of the DMI, revealing the characteristic 1/thickness dependence with one order of magnitude longer decay length compared to metallic layers. We combine chiral spin structures and spinorbit torques for efficient switching and identify skyrmions that allow us to establish the GGG/TmIG interface as the origin of the DMI.The Dzyaloshinskii-Moriya interaction (DMI), an asymmetric exchange interaction, has been intensely studied due to the formation of chiral spin textures such as magnetic

We fabricated quasiantiferromagnetic (quasi-AFM) layers with alternating antiparallel magnetization in the neighboring domains via 90° magnetic coupling through an Fe-O layer. We investigated the magnetic properties and the relationship between the magnetic domain size and the 90° magnetic coupling via experiments and calculations. Two types of samples with a Ru buffer and a (Ni80Fe20)Cr40 buffer were prepared, and we found that with the NiFeCr buffer, the sample has a flatter Fe-O layer, leading to stronger 90° magnetic coupling and a smaller domain size compared with the Ru buffer sample. This trend is well explained by the bilinear and biquadratic coupling coefficients, A12 and B12, in Landau–Lifshitz–Gilbert simulations, suggesting the possibility of using both AFM and FM properties by controlling the quasi-AFM domain size.

This paper reports that Ta 50 W 50 alloy has a higher spin Hall angle than that of βW by measuring the spin Seebeck coefficients for Fe 5 Y 3 O 12 (YIG)/Ru/Ta 50 W 50 and YIG/Ru/W systems. The spin Seebeck coefficient increased by inserting Ru, and the YIG/Ru/Ta 50 W 50 system achieved 2.4 times the magnitude of spin Seebeck coefficient of the conventional YIG/ Pt system although Ru and Ta 50 W 50 have spin Hall angles with opposite signs. Ru seems to recover the spin mixing conductance that is decreased by Ta-W oxidation at its interface with YIG. To enhance the spin Seebeck coefficient, materials having a high spin Hall angle can be combined with materials having a high spin mixing conductance.

We investigated the current-induced domain wall motion (CIDWM) in Pt(3 nm)/TbxCo1-x(6 nm) alloy wires with various Tb composition (x). We found that the threshold current density (Jth) for the CIDWM in the TbxCo1-x alloy wires decreases with increasing x. In particular, the Jth with x = 0.37 is almost 3 times smaller than that with x = 0.23. We estimated Dzyaloshinskii-Moriya interaction (DMI) effective field (HDMI) by measuring CIDWM in a longitudinal magnetic field. We found that DMI constant (D) estimated by the HDMI also strongly depends on x. The size of the DMI may be modified by changing electronegativity or local atomic arrangement in Tb-Co alloy. These results suggest that Tb can induce strong HDMI and effectively affect CIDWM in TbxCo1-x alloy wires.