Mechanism of large magnetoresistance in Co2MnSi/Ag/Co2MnSi devices with current perpendicular to the plane

被引:180
作者
Sakuraba, Y. [1 ]
Izumi, K. [1 ]
Iwase, T. [1 ]
Bosu, S. [1 ]
Saito, K. [1 ]
Takanashi, K. [1 ]
Miura, Y. [2 ,3 ]
Futatsukawa, K. [2 ,3 ]
Abe, K. [2 ,3 ]
Shirai, M. [2 ,3 ]
机构
[1] Tohoku Univ, IMR, Aoba Ku, Sendai, Miyagi 9808577, Japan
[2] Tohoku Univ, RIEC, Aoba Ku, Sendai, Miyagi 9808577, Japan
[3] Tohoku Univ, CSIS, Aoba Ku, Sendai, Miyagi 9808577, Japan
关键词
GIANT MAGNETORESISTANCE; HEUSLER ALLOY; MULTILAYERS; FILM;
D O I
10.1103/PhysRevB.82.094444
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
Fully epitaxial current-perpendicular-to-plane giant magnetoresistance (MR) devices with half-metallic Co2MnSi (CMS) electrodes and a Ag spacer were fabricated to investigate the relationship between the chemical ordering in CMS and its MR properties, including bulk and interface spin-asymmetry coefficients beta and gamma. CMS/Ag/CMS annealed at 550 degrees C shows the largest MR ratio: 36.4% and 67.2% at RT and 110 K, respectively. An analysis based on Valet-Fert's model reveals large spin asymmetry (gamma>0.8) at the CMS/Ag interface, which contributes predominantly to the large MR ratio observed. First-principles ballistic conductance calculations for (001)-CMS/Ag/CMS predict a high majority-spin electron conductance, which could be the origin of the large gamma observed in this study.
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页数:5
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