Recently, the generation, detection, and manipulation of pure spin current through spin-orbit torque in 3d magnets, including ferromagnet and antiferromagnet, are attracting much attention. I will discuss in this talk four aspects in this field where the 3d magnets play the major roles; The spin current enhancement through spin fluctuations in 3d spin-glass Cu1-xMnx alloys [1]; The polarity-controlled field-free spin-orbit torque (SOT) switching via 3d Cr in perpendicular magnetized heterostructures [2]; The absence of evidence of SOT switching in antiferromagnetic insulator NiO [3]; And the magnetization-dependent spin Hall effect in a perpendicular magnetized film Pt/Co/Pt [4]. From these works, we demonstrate that although the switching of the 3d antiferromagnetic Néel vector remains a great challenge, the 3d magnets are efficient in tuning the spin current transmission, function as well as 5d noble metals in SOT switching device, and are able to allow arbitrary spin accumulation at the film surface set by their magnetization. These studies broaden our understanding of pure spin current in 3d magnets and would offer significant advantages developing electrically controlled energy-efficient spintronics devices.

[1] Po-Hsun Wu, Yen-Chang Tu, Danru Qu, Hsia-Ling Liang, Shang-Fan Lee, and Ssu-Yen Huang*, Phys. Rev. B 101, 104413 (2020)
[2] T. C. Chuang, C. F. Pai, and S. Y. Huang*, Phys. Rev. Applied 11, 061005 (2019) (Letter).
[3] C. C. Chiang, S. Y. Huang*, D. Qu, P. H. Wu, C. L. Chien, Phys. Rev. Lett., 123, 227203 (2019).
[4] T. C. Chuang, D. Qu*, S. Y. Huang*, and S. F. Lee, Phys. Rev. Research, 2, 032053(R) (2020) (Rapid Communications).