Enhanced finite size and interface mixing effects in Iridium Manganese ultra thin films

Sarah Jenkins; Richard Francis Llewelyn Evans

doi:10.1063/1.5038006

Enhanced finite size and interface mixing effects in Iridium Manganese ultra thin films

Sarah Jenkins, Richard Francis Llewelyn Evans

Physics

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

Abstract

The finite size and temperature dependent properties of antiferromagnets are of critical importance to a wide range of spintronic and neuromorphic computing devices. Here we present atomistic simu- lations of IrMn, one of the most technologically important antiferromagnets, in both the ordered (L12) and disordered (γ) phases. We have found that antiferromagnetic IrMn3 films show a stronger finite size dependence of the Néel temperature than an equivalent ferromagnet due to the existence of spin frustration. We also find that the disordered γ-IrMn3 phase shows a dramatic reduction in the Néel temperature to less than room temperature for films less than 1 nm thick. Interfacial intermixing of the IrMn3 with a non-magnetic Cu capping layer further reduces the Néel temperature for a given film thickness, with a stronger influence on the disordered γ-IrMn3 phase compared to the ordered L12-IrMn3 phase. Our results suggest a larger antiferromagnetic film thickness is required for devices operating at or above room temperature compared to an equivalent ferromagnet, particularly for sputtered films with a high degree of interfacial intermixing.

Original language	English
Article number	152105
Number of pages	5
Journal	Journal of Applied Physics
Volume	124
DOIs	https://doi.org/10.1063/1.5038006
Publication status	Published - 25 Sept 2018

Bibliographical note

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 = "Enhanced finite size and interface mixing effects in Iridium Manganese ultra thin films",

abstract = "The finite size and temperature dependent properties of antiferromagnets are of critical importance to a wide range of spintronic and neuromorphic computing devices. Here we present atomistic simu- lations of IrMn, one of the most technologically important antiferromagnets, in both the ordered (L12) and disordered (γ) phases. We have found that antiferromagnetic IrMn3 films show a stronger finite size dependence of the N{\'e}el temperature than an equivalent ferromagnet due to the existence of spin frustration. We also find that the disordered γ-IrMn3 phase shows a dramatic reduction in the N{\'e}el temperature to less than room temperature for films less than 1 nm thick. Interfacial intermixing of the IrMn3 with a non-magnetic Cu capping layer further reduces the N{\'e}el temperature for a given film thickness, with a stronger influence on the disordered γ-IrMn3 phase compared to the ordered L12-IrMn3 phase. Our results suggest a larger antiferromagnetic film thickness is required for devices operating at or above room temperature compared to an equivalent ferromagnet, particularly for sputtered films with a high degree of interfacial intermixing.",

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AB - The finite size and temperature dependent properties of antiferromagnets are of critical importance to a wide range of spintronic and neuromorphic computing devices. Here we present atomistic simu- lations of IrMn, one of the most technologically important antiferromagnets, in both the ordered (L12) and disordered (γ) phases. We have found that antiferromagnetic IrMn3 films show a stronger finite size dependence of the Néel temperature than an equivalent ferromagnet due to the existence of spin frustration. We also find that the disordered γ-IrMn3 phase shows a dramatic reduction in the Néel temperature to less than room temperature for films less than 1 nm thick. Interfacial intermixing of the IrMn3 with a non-magnetic Cu capping layer further reduces the Néel temperature for a given film thickness, with a stronger influence on the disordered γ-IrMn3 phase compared to the ordered L12-IrMn3 phase. Our results suggest a larger antiferromagnetic film thickness is required for devices operating at or above room temperature compared to an equivalent ferromagnet, particularly for sputtered films with a high degree of interfacial intermixing.

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