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Temperature‐Dependent Spin–Orbit Torques in Perpendicular Magnetic [Co/Ni] N /TbCo Composite Films
Author(s) -
Xue Hongwei,
Chen Shaohai,
Wu Di,
Zhu Weihua,
Zhang Yuanyuan,
Duan Chungang,
Chen Jingsheng,
Jin Qingyuan,
Zhang Zongzhi
Publication year - 2019
Publication title -
advanced electronic materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.25
H-Index - 56
ISSN - 2199-160X
DOI - 10.1002/aelm.201900014
Subject(s) - materials science , magnetization , condensed matter physics , ferromagnetism , composite number , perpendicular , saturation (graph theory) , spin (aerodynamics) , magnetic field , composite material , physics , thermodynamics , geometry , mathematics , quantum mechanics , combinatorics
The temperature ( T ) dependence of spin–orbit torque (SOT) efficiencies and magnetic properties are investigated in antiferromagnetically coupled Ta/Cu/[Co/Ni] N /TbCo perpendicular composite films. By changing the Co/Ni repetition number N , the magnetization compensation temperature T M can be widely modulated, decreasing from 295 K for N = 0 to below 10 K for N = 2. From temperature‐dependent harmonic Hall measurements, it is shown that damping–like SOT field per current density χ DL = H DL / J ac varies in a similar way to the net saturation magnetization M S and reaches a maximum at T = T M , whereas field‐like H FL /J ac is nearly independent with T . The observed slight deviation between χ DL and 1/M S versus T curves at reduced temperatures is attributed to the increased spin Hall angle and interfacial spin transparency. It is found that the SOT efficiency ξ varies from −0.04 to −0.06 and even to −0.13 for N = 0, 1 and 2, respectively, suggesting ξ is intensively dependent on the details of the Ta/ferromagnet (FM) interface and the FM layer material. These results provide more insight into the SOT effects for exchange‐coupled perpendicular composite structures, which are valuable for developing high‐performance SOT devices.