Negative spin Hall magnetoresistance of Pt on the bulk easy-plane antiferromagnet NiO
Negative spin Hall magnetoresistance of Pt on the bulk easy-plane antiferromagnet NiO
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DOI：
10.1063/1.4997588
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发表时间：
2017-07-31
影响因子：
4
通讯作者：
van Wees, Bart J.
中科院分区：
文献类型：
--
作者：
Hoogeboom, Geert R.;Aqeel, Aisha;van Wees, Bart J.
本文报道了反铁磁NiO（111）单晶上Pt霍尔棒的自旋霍尔磁电阻（SMR）测量。在较宽的温度范围内以及强于0.25T的磁场下观察到与常规SMR符号相反的SMR。SMR的负符号可以通过磁矩的排列几乎垂直于反铁磁体的易平面（111）内的外部磁场来解释。磁矩排列和外部磁场方向的这种相关性仅通过材料的易平面性质来实现，而不需要与额外的铁磁体进行任何交换耦合。SMR信号强度随着温度的升高而降低，主要是由于包括波动的Neel阶的降低。增加的磁场增加SMR信号强度，因为存在更少的畴，并且在高磁场下更强地操纵磁矩。SMR在6 T的外加磁场下饱和，导致类似于10（18）Ω（-1）m（-2）的自旋混合电导，这与绝缘亚铁磁体（如钇铁石榴石）上的Pt相当。氩等离子体处理使自旋混合电导加倍。出版社：AIP Publishing
We report on spin Hall magnetoresistance (SMR) measurements of Pt Hall bars on antiferromagnetic NiO(111) single crystals. An SMR with a sign opposite to conventional SMR is observed over a wide range of temperatures as well as magnetic fields stronger than 0.25 T. The negative sign of the SMR can be explained by the alignment of magnetic moments being almost perpendicular to the external magnetic field within the easy plane (111) of the antiferromagnet. This correlation of magnetic moment alignment and the external magnetic field direction is realized just by the easy-plane nature of the material without the need of any exchange coupling to an additional ferromagnet. The SMR signal strength decreases with increasing temperature, primarily due to the decrease in Neel order by including fluctuations. An increasing magnetic field increases the SMR signal strength as there are fewer domains, and the magnetic moments are more strongly manipulated at high magnetic fields. The SMR is saturated at an applied magnetic field of 6 T, resulting in a spin-mixing conductance of similar to 10(18) Omega(-1) m(-2), which is comparable to that of Pt on insulating ferrimagnets such as yttrium iron garnet. An argon plasma treatment doubles the spin-mixing conductance. Published by AIP Publishing.