Current-driven fast magnetic octupole domain-wall motion in noncollinear antiferromagnets
Mingxing Wu, Taishi Chen, Takuya Nomoto, Yaroslav Tserkovnyak, Hironari Isshiki, Y. Nakatani, Tomoya Higo, Takahiro Tomita, Kouta Kondou, Ryotaro Arita, Satoru Nakatsuji, Y. Otani
Abstract
Abstract Antiferromagnets (AFMs) have the natural advantages of terahertz spin dynamics and negligible stray fields, thus appealing for use in domain-wall applications. However, their insensitive magneto-electric responses make controlling them in domain-wall devices challenging. Recent research on noncollinear chiral AFMs Mn 3 X (X = Sn, Ge) enabled us to detect and manipulate their magnetic octupole domain states. Here, we demonstrate a current-driven fast magnetic octupole domain-wall (MODW) motion in Mn 3 X. The magneto-optical Kerr observation reveals the Néel-like MODW of Mn 3 Ge can be accelerated up to 750 m s -1 with a current density of only 7.56 × 10 10 A m -2 without external magnetic fields. The MODWs show extremely high mobility with a small critical current density. We theoretically extend the spin-torque phenomenology for domain-wall dynamics from collinear to noncollinear magnetic systems. Our study opens a new route for antiferromagnetic domain-wall-based applications.