講演情報
[18a-S2_201-3]Isothermal manipulation of exchange bias effect induced by the chiral antiferromagnet Mn3Sn
〇(D)Mihiro Asakura1, Tomoya Higo2,1,3, Takumi Matsuo4,1, Yutaro Tsushima1, Shun'ichiro Kurosawa1, Ryota Uesugi5,1, Daisuke Nishio-Hamane3, Satoru Nakatsuji1,3,4,6 (1.Dept. of Phys., UTokyo, 2.Dept. of EEE, Keio Univ., 3.ISSP, UTokyo, 4.IQM, Johns Hopkins Univ., 5.Grad. Sch. Sci. Eng., Ibaraki Univ., 6.TSQI, UTokyo)
キーワード：
antiferromagnet、exchange bias、spintronics
Exchange bias effect emerging at the interface between a ferromagnet (FM) and antiferromagnet (AFM) is one of the important phenomena in spintronics to fix a specific magnetization direction of a FM and widely used in reference layers.[1] In a typical FM/AFM, a field cooling process from temperatures above the Néel temperature of the AFM is used to set exchange bias and it cannot be readily manipulated without a temperature change. Recently, methods to control exchange bias without changing temperature have been intensively investigated to enhance the controllability of the effect and realize AFM-based spintronics with ultrafast spin dynamics. In metallic systems, spin-orbit torque (SOT) has been used to manipulate the exchange bias, where only changes in surface uncompensated spins of AFMs breaking time-reversal symmetry are considered.[2]
In this study, we focused on AFMs with broken macroscopic time-reversal symmetry, specifically the chiral AFM Mn3Sn.[3,4] Its magnetic order can be controlled by various methods analogous to those for FMs, such as external magnetic fields, SOT, and exchange bias effect.[4,5,6] We synthesized bilayers composed of Mn3Sn and various FMs and examined the induced exchange bias effect. We revealed that the exchange bias effect in this system can be switched by (i) conventional field cooling process, (ii) isothermal application of magnetic field at room temperature, and (iii) replacement of the ferromagnetic materials. The temperature dependence of the effect indicates that its enhanced controllability arises from the macroscopically broken time-reversal symmetry.
References
[1] W. H. Meiklejohn et al., Phys. Rev. (1956).
[2] P. H. Lin et al., Nat. Mater (2019).<br/>[3] M. Asakura et al., Nano Lett. (2025).
[4] S. Nakatsuji et al., Nature (2015).
[5] H. Tsai et al., Nature (2020).
[6] M. Asakura et al., Adv. Mater. (2024).
In this study, we focused on AFMs with broken macroscopic time-reversal symmetry, specifically the chiral AFM Mn3Sn.[3,4] Its magnetic order can be controlled by various methods analogous to those for FMs, such as external magnetic fields, SOT, and exchange bias effect.[4,5,6] We synthesized bilayers composed of Mn3Sn and various FMs and examined the induced exchange bias effect. We revealed that the exchange bias effect in this system can be switched by (i) conventional field cooling process, (ii) isothermal application of magnetic field at room temperature, and (iii) replacement of the ferromagnetic materials. The temperature dependence of the effect indicates that its enhanced controllability arises from the macroscopically broken time-reversal symmetry.
References
[1] W. H. Meiklejohn et al., Phys. Rev. (1956).
[2] P. H. Lin et al., Nat. Mater (2019).<br/>[3] M. Asakura et al., Nano Lett. (2025).
[4] S. Nakatsuji et al., Nature (2015).
[5] H. Tsai et al., Nature (2020).
[6] M. Asakura et al., Adv. Mater. (2024).