journal article·2019-12-01Open access

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

AIP Advances· Volume 9· Issue 12

Abstract

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.
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Research context

OpenAlex topics: Heusler alloys: electronic and magnetic properties · Magnetic properties of thin films · Wireless Power Transfer Systems

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Affiliations

Department of Applied Physics, Tohoku University 1 , Sendai 980-8579, Japan

Center for Science and Innovation in Spintronics (Core Research Cluster) Organization for Advanced Studies, Tohoku University 2 , Sendai 980-8577, Japan

Center for Spintronics Research Network, Tohoku University 3 , Sendai 980-8577, Japan

Department of Electronic Engineering, Tohoku University 4 , Sendai 980-8579, Japan

Funding

Center for Science and Innovation in Spintronics · Center for Spintronics Research · Strategic Promotion of Innovative R and D · Japan Science and Technology Agency

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