Efficient integration of self-assembled organic monolayer tunnel barriers in large area pinhole-free magnetic tunnel junctions

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Main Authors: Dehaghani, Maryam S., Aguinet, Sophie Guézo, Pottier, Arnaud Le, Ababou-Girard, Soraya, Bernard, Rozenn, Tricot, Sylvain, Schieffer, Philippe, Lépine, Bruno, Solal, Francine, Turban, Pascal
Format: Preprint
Published: 2025
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author Dehaghani, Maryam S.
Aguinet, Sophie Guézo
Pottier, Arnaud Le
Ababou-Girard, Soraya
Bernard, Rozenn
Tricot, Sylvain
Schieffer, Philippe
Lépine, Bruno
Solal, Francine
Turban, Pascal
author_facet Dehaghani, Maryam S.
Aguinet, Sophie Guézo
Pottier, Arnaud Le
Ababou-Girard, Soraya
Bernard, Rozenn
Tricot, Sylvain
Schieffer, Philippe
Lépine, Bruno
Solal, Francine
Turban, Pascal
contents Magneto-transport properties in hybrid magnetic tunnel junctions (MTJs) integrating self-assembled monolayers (SAMs) as tunnel barriers are critically influenced by spinterface effects, which arise from the electronic properties at ferromagnet (FM)/SAM interfaces. Understanding the mechanisms governing spinterface formation in well-controlled model systems is essential for the rational design of efficient molecular spintronic devices. However, the fabrication of FM/SAM/FM systems remains a significant challenge due to the difficulty in preventing electrical shorts through the SAM tunnel barrier during top FM electrode deposition. In this study, we address these challenges by developing model hybrid MTJs incorporating alkanethiol SAM tunnel barriers grafted under ultra-high vacuum conditions onto single-crystalline Fe(001) bottom electrodes. A soft-landing deposition method is used for the deposition of a top Co FM electrode. The deposition process and the electronic properties of the FM/SAM interfaces are first studied by spatially integrated X-ray photoelectron spectroscopy. Furthermore, ballistic electron emission microscopy (BEEM) and spectroscopy are used to investigate the lateral homogeneity of the organic barrier. Optimal soft-landing deposition conditions allows the preparation of homogeneous Co/SAM interfaces with no evidence of metal diffusion through the SAM at the nanoscale. These observations are further confirmed at the micron-scale by the high-yield patterning of large area (5*5um2) MTJs presenting fingerprints of electron tunneling through the SAM. These findings provide critical insights into the fabrication and optimization of molecular spintronic devices, paving the way for advancements in hybrid MTJ technology.
format Preprint
id arxiv_https___arxiv_org_abs_2507_19330
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Efficient integration of self-assembled organic monolayer tunnel barriers in large area pinhole-free magnetic tunnel junctions
Dehaghani, Maryam S.
Aguinet, Sophie Guézo
Pottier, Arnaud Le
Ababou-Girard, Soraya
Bernard, Rozenn
Tricot, Sylvain
Schieffer, Philippe
Lépine, Bruno
Solal, Francine
Turban, Pascal
Applied Physics
Materials Science
Magneto-transport properties in hybrid magnetic tunnel junctions (MTJs) integrating self-assembled monolayers (SAMs) as tunnel barriers are critically influenced by spinterface effects, which arise from the electronic properties at ferromagnet (FM)/SAM interfaces. Understanding the mechanisms governing spinterface formation in well-controlled model systems is essential for the rational design of efficient molecular spintronic devices. However, the fabrication of FM/SAM/FM systems remains a significant challenge due to the difficulty in preventing electrical shorts through the SAM tunnel barrier during top FM electrode deposition. In this study, we address these challenges by developing model hybrid MTJs incorporating alkanethiol SAM tunnel barriers grafted under ultra-high vacuum conditions onto single-crystalline Fe(001) bottom electrodes. A soft-landing deposition method is used for the deposition of a top Co FM electrode. The deposition process and the electronic properties of the FM/SAM interfaces are first studied by spatially integrated X-ray photoelectron spectroscopy. Furthermore, ballistic electron emission microscopy (BEEM) and spectroscopy are used to investigate the lateral homogeneity of the organic barrier. Optimal soft-landing deposition conditions allows the preparation of homogeneous Co/SAM interfaces with no evidence of metal diffusion through the SAM at the nanoscale. These observations are further confirmed at the micron-scale by the high-yield patterning of large area (5*5um2) MTJs presenting fingerprints of electron tunneling through the SAM. These findings provide critical insights into the fabrication and optimization of molecular spintronic devices, paving the way for advancements in hybrid MTJ technology.
title Efficient integration of self-assembled organic monolayer tunnel barriers in large area pinhole-free magnetic tunnel junctions
topic Applied Physics
Materials Science
url https://arxiv.org/abs/2507.19330