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Tailoring Multilevel‐Stable Remanence States in Exchange‐Biased System through Spin‐Orbit Torque
Author(s) -
Yun Jijun,
Bai Qiaoning,
Yan Ze,
Chang Meixia,
Mao Jian,
Zuo Yalu,
Yang Dezheng,
Xi Li,
Xue Desheng
Publication year - 2020
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201909092
Subject(s) - remanence , neuromorphic engineering , ferromagnetism , condensed matter physics , materials science , exchange bias , antiferromagnetism , spintronics , magnetic field , physics , computer science , magnetization , magnetic anisotropy , quantum mechanics , artificial neural network , machine learning
Multilevel remanence states have potential applications in ultra‐high‐density storage and neuromorphic computing. Continuous tailoring of the multilevel remanence states by spin‐orbit torque (SOT) is reported in perpendicularly magnetized Pt/Co/IrMn heterostructures. Double‐biased hysteresis loops with only one remanence state can be tuned from the positively or negatively single‐biased loops by SOT controlled sign of the exchange‐bias field. The remanence states associated with the heights of the sub‐loops are continually changed by tuning the ratio of the positively and negatively oriented ferromagnetic domains. The multilevel storage cells are demonstrated by reading the remanent Hall resistance through changing the sign and/or the magnitude of current pulse. The synaptic plasticity behaviors for neuromorphic computing are also simulated by varying the remanent Hall resistance under the consecutive current pulses. This work demonstrates that SOT is an effective method to tailor the remanence states in the double‐biased heavy metal/ferromagnetic/antiferromagnetic system. The multilevel‐stable remanence states driven by SOT show potential applications in future multilevel memories and neuromorphic computing devices.