Perpendicular Anisotropy Controlled by Seed and Capping Layers of Heusler-Alloy Films

William James Frost; Marjan Samiepour; Atsufumi Hirohata

doi:10.1109/TED.2021.3105490

Perpendicular Anisotropy Controlled by Seed and Capping Layers of Heusler-Alloy Films

William James Frost, Marjan Samiepour, Atsufumi Hirohata

Research output: Contribution to journal › Article › peer-review

Abstract

Half-metallic Heusler alloys typically have in-plane magnetic anisotropy, which can be converted to perpendicular by attaching MgO or heavy metal, e.g., Pt, layers as similarly applied for conventional ferromagnets. Recently we have found body-centered cubic (bcc) seed layers, e.g., V and W, to induce perpendicular anisotropy in Heusler-alloy films above, however, they show small giant magnetoresistance (GMR) ratios in spin-valve structures to date. This is partially because of the large resistivity of the seed layer and the nonmagnetic layer in the spin-valve. In this study, we have systematically investigated nonmagnetic overlayers and have found that a Ag layer best maintains the perpendicular anisotropy. The corresponding GMR devices have then been fabricated and characterized, achieving the GMR ratio of 0.03% at room temperature. Such bcc seed layers can offer an alternative method for perpendicularlymagnetizedGMRjunctions for applications.

Original language	English
Pages (from-to)	1629-1633
Journal	IEEE Transactions on Electron Devices
Volume	69
Issue number	4
Early online date	13 Aug 2021
DOIs	https://doi.org/10.1109/TED.2021.3105490
Publication status	Published - 6 Sept 2021

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This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy. Further copying may not be permitted; contact the publisher for details

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Cite this

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title = "Perpendicular Anisotropy Controlled by Seed and Capping Layers of Heusler-Alloy Films",

abstract = "Half-metallic Heusler alloys typically have in-plane magnetic anisotropy, which can be converted to perpendicular by attaching MgO or heavy metal, e.g., Pt, layers as similarly applied for conventional ferromagnets. Recently we have found body-centered cubic (bcc) seed layers, e.g., V and W, to induce perpendicular anisotropy in Heusler-alloy films above, however, they show small giant magnetoresistance (GMR) ratios in spin-valve structures to date. This is partially because of the large resistivity of the seed layer and the nonmagnetic layer in the spin-valve. In this study, we have systematically investigated nonmagnetic overlayers and have found that a Ag layer best maintains the perpendicular anisotropy. The corresponding GMR devices have then been fabricated and characterized, achieving the GMR ratio of 0.03% at room temperature. Such bcc seed layers can offer an alternative method for perpendicularlymagnetizedGMRjunctions for applications.",

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AB - Half-metallic Heusler alloys typically have in-plane magnetic anisotropy, which can be converted to perpendicular by attaching MgO or heavy metal, e.g., Pt, layers as similarly applied for conventional ferromagnets. Recently we have found body-centered cubic (bcc) seed layers, e.g., V and W, to induce perpendicular anisotropy in Heusler-alloy films above, however, they show small giant magnetoresistance (GMR) ratios in spin-valve structures to date. This is partially because of the large resistivity of the seed layer and the nonmagnetic layer in the spin-valve. In this study, we have systematically investigated nonmagnetic overlayers and have found that a Ag layer best maintains the perpendicular anisotropy. The corresponding GMR devices have then been fabricated and characterized, achieving the GMR ratio of 0.03% at room temperature. Such bcc seed layers can offer an alternative method for perpendicularlymagnetizedGMRjunctions for applications.

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