Half-Metallic Bandgap Measurement Using Circularly-Polarised Infrared Light

Tariq Fahad H Alhuwaymel; Takahide Kubota; Jun-Young Kim; Koki Takanashi; Atsufumi Hirohata

doi:10.1142/S2010324723500078

Half-Metallic Bandgap Measurement Using Circularly-Polarised Infrared Light

Tariq Fahad H Alhuwaymel, Takahide Kubota, Jun-Young Kim, Koki Takanashi, Atsufumi Hirohata

Electronic Engineering

Research output: Contribution to journal › Review article › peer-review

Abstract

One avenue towards next generation spintronic devices is to develop half-metallic ferromagnets with 100% spin polarisation and Curie temperature above room temperature. Half-metallic ferromagnets have unique density of states, where the majority spins are metallic but the minority spins are semiconducting with the Fermi level lying within an energy gap. To date, the half-metallic bandgap has been predominantly estimated using Jullière’s formula in a magnetic tunnel junction or measured by the Andreev reflection at low temperature, both of which are very sensitive to the surface/interface spin polarisation. Alternative optical methods such as photoemission have also been employed but with a complicated and expensive set-up. In this study, we developed and optimised a new technique to directly measure the half-metallic bandgap by introducing circularly-polarised infrared light to excite minority spins. The absorption of the light represents the bandgap under a magnetic field to saturate the magnetisation of a sample. This technique can be used to provide simple evaluation of a half-metallic film.

Original language	English
Journal	Spin
Early online date	18 Mar 2023
DOIs	https://doi.org/10.1142/S2010324723500078
Publication status	E-pub ahead of print - 18 Mar 2023

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

Access to Document

10.1142/S2010324723500078

Half-Metallic Bandgap Measurement Using Circularly Polarized Infrared Light
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
Accepted author manuscript, 10.2 MB

Cite this

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title = "Half-Metallic Bandgap Measurement Using Circularly-Polarised Infrared Light",

abstract = "One avenue towards next generation spintronic devices is to develop half-metallic ferromagnets with 100% spin polarisation and Curie temperature above room temperature. Half-metallic ferromagnets have unique density of states, where the majority spins are metallic but the minority spins are semiconducting with the Fermi level lying within an energy gap. To date, the half-metallic bandgap has been predominantly estimated using Julli{\`e}re{\textquoteright}s formula in a magnetic tunnel junction or measured by the Andreev reflection at low temperature, both of which are very sensitive to the surface/interface spin polarisation. Alternative optical methods such as photoemission have also been employed but with a complicated and expensive set-up. In this study, we developed and optimised a new technique to directly measure the half-metallic bandgap by introducing circularly-polarised infrared light to excite minority spins. The absorption of the light represents the bandgap under a magnetic field to saturate the magnetisation of a sample. This technique can be used to provide simple evaluation of a half-metallic film.",

author = "Alhuwaymel, {Tariq Fahad H} and Takahide Kubota and Jun-Young Kim and Koki Takanashi and Atsufumi Hirohata",

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AU - Kim, Jun-Young

AU - Takanashi, Koki

AU - Hirohata, Atsufumi

N1 - 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

PY - 2023/3/18

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N2 - One avenue towards next generation spintronic devices is to develop half-metallic ferromagnets with 100% spin polarisation and Curie temperature above room temperature. Half-metallic ferromagnets have unique density of states, where the majority spins are metallic but the minority spins are semiconducting with the Fermi level lying within an energy gap. To date, the half-metallic bandgap has been predominantly estimated using Jullière’s formula in a magnetic tunnel junction or measured by the Andreev reflection at low temperature, both of which are very sensitive to the surface/interface spin polarisation. Alternative optical methods such as photoemission have also been employed but with a complicated and expensive set-up. In this study, we developed and optimised a new technique to directly measure the half-metallic bandgap by introducing circularly-polarised infrared light to excite minority spins. The absorption of the light represents the bandgap under a magnetic field to saturate the magnetisation of a sample. This technique can be used to provide simple evaluation of a half-metallic film.

AB - One avenue towards next generation spintronic devices is to develop half-metallic ferromagnets with 100% spin polarisation and Curie temperature above room temperature. Half-metallic ferromagnets have unique density of states, where the majority spins are metallic but the minority spins are semiconducting with the Fermi level lying within an energy gap. To date, the half-metallic bandgap has been predominantly estimated using Jullière’s formula in a magnetic tunnel junction or measured by the Andreev reflection at low temperature, both of which are very sensitive to the surface/interface spin polarisation. Alternative optical methods such as photoemission have also been employed but with a complicated and expensive set-up. In this study, we developed and optimised a new technique to directly measure the half-metallic bandgap by introducing circularly-polarised infrared light to excite minority spins. The absorption of the light represents the bandgap under a magnetic field to saturate the magnetisation of a sample. This technique can be used to provide simple evaluation of a half-metallic film.

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