Quantitative visualization of thermally enhanced perpendicular shape anisotropy STT-MRAM nanopillars

Almeida, T. P. , Lequeux, S., Palomino, A., Sousa, R. C., Fruchart, O., Prejbeanu, I.-L., Dieny, B., Masseboeuf, A. and Cooper, D. (2022) Quantitative visualization of thermally enhanced perpendicular shape anisotropy STT-MRAM nanopillars. Nano Letters, 22(10), pp. 4000-4005. (doi: 10.1021/acs.nanolett.2c00597) (PMID:35576455)

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Abstract

Perpendicular shape anisotropy (PSA) offers a practical solution to downscale spin-transfer torque magnetoresistive random-access memory (STT-MRAM) beyond the sub-20 nm technology node while retaining thermal stability. However, our understanding of the thermomagnetic behavior of PSA-STT-MRAM is often indirect, relying on magnetoresistance measurements and micromagnetic modeling. Here, the magnetism of a NiFe PSA-STT-MRAM nanopillar is investigated using off-axis electron holography, providing spatially resolved magnetic information as a function of temperature. Magnetic induction maps reveal the micromagnetic configuration of the NiFe storage layer (∼60 nm high, ≤20 nm diameter), confirming the PSA induced by its 3:1 aspect ratio. In situ heating demonstrates that the PSA of the storage layer is maintained up to at least 250 °C, and direct quantitative measurements reveal a moderate decrease of magnetic induction. Hence, this study shows explicitly that PSA provides significant stability in STT-MRAM applications that require reliable performance over a range of operating temperatures.

Item Type:Articles
Additional Information:This work, carried out on the Platform for Nanocharacterisation (PFNC), was supported by the “Recherches Technologiques de Base” program of the French National Research Agency (ANR) via Carnot Funding and the European Research Council (ERC MAGICAL, 669204).
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Almeida, Dr Trevor
Authors: Almeida, T. P., Lequeux, S., Palomino, A., Sousa, R. C., Fruchart, O., Prejbeanu, I.-L., Dieny, B., Masseboeuf, A., and Cooper, D.
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:Nano Letters
Publisher:American Chemical Society
ISSN:1530-6984
ISSN (Online):1530-6992
Published Online:16 May 2022
Copyright Holders:Copyright © 2022 American Chemical Society
First Published:First published in Nano Letters 22(10): 4000-4005
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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