Large influence of capping layers on tunnel magnetoresistance in magnetic tunnel junctions

被引：30

作者：

Zhou, Jiaqi ^{[1
,2
,3
]}

Zhao, Weisheng ^{[1
,2
]}

Wang, Yin ^{[4
,5
]}

Peng, Shouzhong ^{[1
,2
]}

Qiao, Junfeng ^{[1
,2
]}

Su, Li ^{[1
,2
,3
]}

Zeng, Lang ^{[1
,2
]}

Lei, Na ^{[1
,2
]}

Liu, Lei ^{[6
]}

Zhang, Youguang ^{[1
,2
]}

Bournel, Arnaud ^{[3
]}

机构：

[1] Beihang Univ, Fert Beijing Inst, BDBC, Beijing 100191, Peoples R China

[2] Beihang Univ, Sch Elect & Informat Engn, Beijing 100191, Peoples R China

[3] Univ Paris Saclay, Univ Paris Sud, CNRS, Ctr Nanosci & Nanotechnol, F-91405 Orsay, France

[4] Univ Hong Kong, Dept Phys, Hong Kong, Hong Kong, Peoples R China

[5] Univ Hong Kong, Ctr Theoret & Computat Phys, Hong Kong, Hong Kong, Peoples R China

[6] Nanoacad Technol Inc, Brossard, PQ J4Z 1A7, Canada

来源：

APPLIED PHYSICS LETTERS | 2016年 / 109卷 / 24期

基金：

中国国家自然科学基金;

关键词：

ROOM-TEMPERATURE; SPIN; ANISOTROPY;

D O I：

10.1063/1.4972030

中图分类号：

O59 [应用物理学];

学科分类号：

摘要：

It has been reported in experiments that capping layers, which enhance the perpendicular magnetic anisotropy (PMA) of magnetic tunnel junctions (MTJs), induce a great impact on the tunnel magnetoresistance (TMR). To explore the essential influence caused by the capping layers, we carry out ab initio calculations on TMR in the X(001)vertical bar CoFe(001)vertical bar MgO(001)vertical bar CoFe(001)vertical bar X(001) MTJ, where X represents the capping layer material, which can be tungsten, tantalum, or hafnium. We report TMR in different MTJs and demonstrate that tungsten is an ideal candidate for a giant TMR ratio. The transmission spectrum in Brillouin zone is presented. It can be seen that in the parallel condition of MTJ, sharp transmission peaks appear in the minority-spin channel. This phenomenon is attributed to the resonant tunnel transmission effect, and we explained it by the layer-resolved density of states. In order to explore transport properties in MTJs, the density of scattering states was studied from the point of band symmetry. It has been found that CoFe vertical bar tungsten interface blocks scattering states transmission in the anti-parallel condition. This work reports TMR and transport properties in MTJs with different capping layers and proves that tungsten is a proper capping layer material, which would benefit the design and optimization of MTJs. Published by AIP Publishing.

引用

页数：4

共 34 条

[1] Highly stable perpendicular magnetic anisotropies of CoFeB/MgO frames employing W buffer and capping layers [J].