Marketing Chen
Marketing Cai
Recently, Professor Wanjun Jiang research group, State Key Laboratory of Low Dimensional Quantum Physics and Quantum Information Frontier Science Center, Department of Physics from Tsinghua University, took the lead in realizing perpendicular magnetic anisotropy in rare earth permanent magnet SmCo5 thin film materials through interface optimization and nano film preparation technology.
The research group studied the spin-orbitronics torque effect and different types of topological spin structures in SmCo5 thin film. the results thus demonstrate that rare earth permanent magnets could be a new platform for studying interfacial chiral spintronics.The achievement was published in Advanced Functional Material with the title of "Rare-Earth Permanent Magnet SmCo5 for Chiral Interfacial Spin-Orbitronics".
In the widely studied heavy metal / ferromagnetic, the spin orbit moment can effectively manipulate the magnetization, interface to invert the symmetry breaking, and can also derive the skyrmions. These studies can provide new ideas for spin devices in the future, so they are the current research hotspot. While significant progresses have been made in Co, CoFeB, Co2FeAl, CoFeGd based multilayers, it would be intriguing to identify new magnetic multilayers that could enable spin-torque controllability and meanwhile host nanoscale skyrmions. SmCo5 is a wellknown rare-earth permanent magnet, which has been widely investigated for the ultrahigh density recording media due to its large magnetic anisotropy.When applied to interfacial spintronic devices, the thermal stability and storage density of the devices can be improved. In this report, first, thin films made of permanent magnet SmCo5 with perpendicular magnetic anisotropy are synthesized, in which the deterministic SOT switching, enabled by the spin Hall effect, in Pt/SmCo5/Ta trilayer is demonstrated. Further, the stabilization of roomtemperature skyrmions with diameters ≈100 nm in [Pt/SmCo5/Ta]15, together with a skyrmionium-like spin texture in [Pt/SmCo5/Ir]15 multilayers is shown.Based on the material specific parameters, micromagnetic simulations are also carried out. The results confirm the presence of chiral spin textures in this new material family.Through interfacial engineering, the results thus demonstrate that rare earth permanent magnets could be a new platform for studying interfacial chiral spintronics.
The multilayer studied by this research group is synthesized by PVD on 100 nm silicon nitride membrane, which is independently developed and produced by YW MEMS (Suzhou) Co., Ltd. The thinnest silicon nitride membrane produced by YW MEMS can be up to 10 nm, with good mechanical strength, high temperature resistance and surface thermal conductivity under the premise of ensuring super smooth and super clean quality requirements.
a) The sketch of spin currents generated in Pt and Ta layer via the SHE.
b) An optical image of the fabricated Hall-bar device.
Original link:https://onlinelibrary.wiley.com/doi/abs/10.1002/adfm.202104426