Polycrystalline Co2Fe0.4Mn0.6Si Heusler alloy thin films with high B2 ordering and small magnetic anisotropy for magnetic tunnel junction based sensors

Nana Kudo; Mikihiko Oogane; Masakiyo Tsunoda; Yasuo Ando

doi:10.1063/1.5130461

AIP Advances (Dec 2019)

Polycrystalline Co2Fe0.4Mn0.6Si Heusler alloy thin films with high B2 ordering and small magnetic anisotropy for magnetic tunnel junction based sensors

Nana Kudo,
Mikihiko Oogane,
Masakiyo Tsunoda,
Yasuo Ando

Affiliations

Nana Kudo: Department of Applied Physics, Tohoku University, Sendai 980-8579, Japan
Mikihiko Oogane: Department of Applied Physics, Tohoku University, Sendai 980-8579, Japan
Masakiyo Tsunoda: Center for Spintronics Research Network, Tohoku University, Sendai 980-8577, Japan
Yasuo Ando: Department of Applied Physics, Tohoku University, Sendai 980-8579, Japan

DOI: https://doi.org/10.1063/1.5130461
Journal volume & issue: Vol. 9, no. 12
pp. 125036 – 125036-4

Abstract

Read online

To measure the bio magnetic field from the heart and brain at room temperature, the magnetic tunnel junctions (MTJs) based sensor is required to achieve a high sensitivity which is defined as the TMR ratio/2Hk (where Hk is anisotropic magnetic field of the free layer). To realize both high TMR ratio and small Hk, we employed (001)-oriented polycrystalline Co-based Heusler alloy material (Co2Fe0.4Mn0.6Si) for the free layer which is known for its high spin polarization and small Hk. In this study, we optimized the crystal and magnetic properties of Co2Fe0.4Mn0.6Si free layer and succeeded in reducing Hk in polycrystalline CFMS free layer with high B2 ordering. We also demonstrated the linear output of TMR in MTJs fabricated under the optimized condition.

Published in AIP Advances

ISSN: 2158-3226 (Online)
Publisher: AIP Publishing LLC
Country of publisher: United States
LCC subjects: Science: Physics
Website: http://aipadvances.aip.org/

About the journal