Tunneling magnetoresistance of perpendicular CoFeB-based junctions with exchange bias
Tunneling magnetoresistance of perpendicular CoFeB-based junctions with exchange bias
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DOI：
10.1063/1.4985850
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发表时间：
2017-09-14
影响因子：
3.2
通讯作者：
Reiss, Guenter
中科院分区：
文献类型：
--
作者：
Manos, Orestis;Boehnke, Alexander;Reiss, Guenter
近年来，垂直磁化电极与交换偏置膜相结合的磁隧道结引起了人们的广泛关注。在本文中，我们研究了Ta/Pd/IrMn/Co-Fe/Ta/Co-Fe- b /MgO/Co-Fe- b /capping/Pd磁性隧道结的隧道磁阻随封盖层（即Hf或Ta）的变化。在这些叠层中，垂直交换偏置场与垂直磁各向异性相结合。在室温下，与Ta(42.660.7)%相比，hf封顶样品的隧道磁电阻为（47.261.4）%。有趣的是，这一观察结果与Hf的硼吸收比Ta高有关，这阻止了δ(1)通道的抑制，导致更高的隧道磁电阻值。此外，两种样品的软电极矫顽力的温度依赖主要由含热波动的Stoner-Wohlfarth模型描述。在低温下的轻微偏差可归因于由钉住磁层系统产生的软电极上的扭矩。AIP出版社出版。
Recently, magnetic tunnel junctions with perpendicular magnetized electrodes combined with exchange bias films have attracted great interest. In this paper, we examine the tunnel magnetoresistance of Ta/Pd/IrMn/Co-Fe/Ta/Co-Fe-B/MgO/Co-Fe-B/capping/Pd magnetic tunnel junctions dependent on the capping layer, i.e., Hf or Ta. In these stacks, perpendicular exchange bias fields of -500 Oe along with perpendicular magnetic anisotropy are combined. A tunnel magnetoresistance of (47.261.4)% for the Hf-capped sample was determined compared to the Ta one (42.660.7)% at room temperature. Interestingly, this observation is correlated with the higher boron absorption of Hf compared to Ta, which prevents the suppression of the Delta(1) channel and leads to higher tunnel magnetoresistance values. Furthermore, the temperature dependent coercivities of the soft electrodes of both samples are mainly described by the Stoner-Wohlfarth model including thermal fluctuations. Slight deviations at low temperatures can be attributed to a torque on the soft electrode which is generated by the pinned magnetic layer system. Published by AIP Publishing.