Enhanced current-perpendicular-to-plane giant magnetoresistance by improvement of atomic order of Co2FeSi Heusler alloy film through Ag doping

Songtian Li,Subrojati Bosu,Kazuhiro Hono,Taisuke Sasaki,Yuya Sakuraba,Jiamin Chen

doi:10.1063/1.5045175

Abstract

We investigated the effect of Ag doping on atomic order and spin polarization of Co2FeSi Heusler alloy thin films. The Co2FeSi film doped with 3at.%-Ag showed improved degree of B2- and L21-ordering after thermal annealing comparing to Co2FeSi film. Negative sign of anisotropic magnetoresistance suggests the half-metallic nature of Ag-doped Co2FeSi film after annealing at a relatively low temperature of 300 °C. The current-perpendicular-to-plane pseudo spin-valves using the Ag-doped Co2FeSi ferromagnetic (FM) electrodes showed about 1.2 times larger MR ratio than that using the Co2FeSi FM electrodes, reflecting an enhanced spin polarization in Ag-doped Co2FeSi film. Micro-structure analysis revealed the doped Ag was rejected out of Co2FeSi layer after annealing. This study suggests Ag doping to Co-based Heusler compound having no/few solubility with Ag is beneficial for realizing spin-valves with high output at moderate annealing conditions.

Highlights

ARTICLES YOU MAY BE INTERESTED INSongtian Li,1,a Yuya Sakuraba,1,b Taisuke Sasaki,[1] Jiamin Chen,[2] Subrojati Bosu,[1] and Kazuhiro Hono1,2 1National Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047, Japan 2Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8571, Japan (Received 18 June 2018; accepted 18 July 2018; published online 31 July 2018)
We studied the effect of Ag doping (3at.%) on atomic order and spin polarization in Co2FeSi Heusler alloy films
Both the atomic order and crystallinity were improved in the Co2FeSi-Ag film after post annealing, compared with the Co2FeSi film

Summary

ARTICLES YOU MAY BE INTERESTED IN

Songtian Li,1,a Yuya Sakuraba,1,b Taisuke Sasaki,[1] Jiamin Chen,[2] Subrojati Bosu,[1] and Kazuhiro Hono1,2 1National Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047, Japan 2Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8571, Japan (Received 18 June 2018; accepted 18 July 2018; published online 31 July 2018)

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