Spin transfer torque switching in exchangecoupled amorphous GdFeCo/TbFe bilayers for thermally assisted MRAM application
Spin transfer torque switching in exchangecoupled amorphous GdFeCo/TbFe bilayers for thermally assisted MRAM application
复制标题
用于热辅助 MRAM 应用的交换耦合非晶 GdFeCo/TbFe 双层中的自旋转移扭矩切换
DOI：
10.1088/1361-6463/aa5bca
复制
发表时间：
2017
期刊：
影响因子：
--
通讯作者：
J. Han
中科院分区：
文献类型：
--
作者：
B. Dai;Y. Guo;J. Zhu;T. Kato;S. Iwata;S. Tsunashima;L. Yang;J. Han
研究了用于自旋转移扭矩(STT)开关的巨磁电阻(GMR)器件中交换耦合非晶态GdFeCo/TbFe存储层，测量了GMR器件的临界电流密度与温度的关系，讨论了交换耦合双层膜作为热辅助磁随机存取存储器(MRAM)存储层的作用.采用磁控溅射和后续微加工工艺制备了具有不同厚度的非晶态GdFeCo和TbFe双层存储器的GMR器件。为了研究自旋转移扭矩(STT)开关，在GMR器件上施加了脉冲电流。最大磁阻比约为0.15%，双层记忆薄膜的矫顽力随TbFe厚度的增加而增大，随温度的升高而减小。获得了结构为Gd2 1.4(Fe90 Co10)78.6(9 Nm)/Tb16Fe84(1 Nm)的记忆双层膜开关的临界电流密度Jc，最低为2.2×10 7A cm−2。Jc随温度的升高而减小，并与GdFeCo/TbFe双层膜的有效各向异性Kef成比例，这被认为适合于热辅助STT-MRAM的应用。
Exchange-coupled amorphous GdFeCo/TbFe memory layers in giant magneto-resistance (GMR) devices for spin transfer torque (STT) switching have been studied, and temperature dependence of the critical current density of the GMR devices was measured to discuss the effect of exchange-coupled bilayers as a memory layer of the thermally assisted magnetic random access memory (MRAM). The GMR devices having amorphous GdFeCo and TbFe memory bilayers with various thicknesses were prepared by magnetron sputtering and subsequent micro-fabrication processes. A pulsed current was applied to the GMR devices in order to investigate the spin transfer torque (STT) switching. The maximum magneto-resistance (MR) ratio was around 0.15%, and the coercivity of the memory bilayer increased with the TbFe thickness and decreased with elevating temperature. The critical current densities J c to switch the memory bilayer with structure of Gd 21.4 (Fe 90 Co 10) 78.6 (9 nm)/Tb 16 Fe 84 (1 nm) as low as 2.2× 10 7 A cm− 2 was obtained. The J c reduced with increasing the temperature and was found to scale with the effective anisotropy K eff of GdFeCo/TbFe bilayer, which is believed to be suitable for the application of thermally assisted STT-MRAM.