Terahertz spintronic magnetometer (TSM)

A ferromagnetic metal consists of localized electrons and conduction electrons coupled through strong exchange interaction. Together, these localized electrons contribute to the magnetization of the system, while conduction electrons lead to the formation of spin and charge current. Femtosecond out...

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Main Authors: Agarwal, Piyush, Yang, Yingshu, Lourembam, James, Medwal, Rohit, Battiato, Marco, Singh, Ranjan
Other Authors: School of Physical and Mathematical Sciences
Format: Article
Language:English
Published: 2022
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Online Access:https://hdl.handle.net/10356/157912
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-1579122023-02-28T20:06:21Z Terahertz spintronic magnetometer (TSM) Agarwal, Piyush Yang, Yingshu Lourembam, James Medwal, Rohit Battiato, Marco Singh, Ranjan School of Physical and Mathematical Sciences Centre for Disruptive Photonic Technologies (CDPT) The Photonics Institute Science::Physics::Optics and light spintronic terahertz Emission Terahertz Hysteresis Terahertz Charge Current Terahertz Magnetometer THz-H Hysteresis A ferromagnetic metal consists of localized electrons and conduction electrons coupled through strong exchange interaction. Together, these localized electrons contribute to the magnetization of the system, while conduction electrons lead to the formation of spin and charge current. Femtosecond out of equilibrium photoexcitation of ferromagnetic thin films generates a transient spin current at ultrafast timescales that have opened a route to probe magnetism offered by the conduction electrons. In the presence of a neighboring heavy metal layer, the non-equilibrium spin current is converted into a pulsed charge current and gives rise to terahertz (THz) emission. Here, we propose and demonstrate a tool known as the terahertz spintronic magnetometry. The hysteresis loop obtained by sweeping terahertz (THz) pulse amplitude as a function of the magnetic field is in excellent agreement with the vibrating-sample magnetometer measurements. Furthermore, a modified transfer-matrix method employed to model the THz propagation within the heterostructure theoretically elucidates a linear relationship between the THz pulse amplitude and sample magnetization. The strong correlation, thus, reveals spintronic terahertz emission as an ultrafast magnetometry tool with reliable in-plane magnetization detection, highlighting its technological importance in the characterization of ferromagnetic thin-films through terahertz spintronic emission spectroscopy. Agency for Science, Technology and Research (A*STAR) Ministry of Education (MOE) Nanyang Technological University National Research Foundation (NRF) Submitted/Accepted version R.S. would like to acknowledge National Research Foundation, Singapore, for the support through No. NRF-CRP23-2019-0005. M.B. would like to acknowledge Nanyang Technological University, NAP-SUG grant. J.L. would like to acknowledge funding support from SpOT-LITE programme (Agency for Science, Technology and Research, A STAR Grant No. A18A6b0057) through RIE2020 funds from Singapore. The authors thank Tan Hang Khume for help in film deposition. R.S. and R.M. would like to acknowledge the Ministry of Education (MOE) for Grant No. MOE2019-T2-1-058 2022-05-16T06:53:27Z 2022-05-16T06:53:27Z 2022 Journal Article Agarwal, P., Yang, Y., Lourembam, J., Medwal, R., Battiato, M. & Singh, R. (2022). Terahertz spintronic magnetometer (TSM). Applied Physics Letters, 120(16), 161104-. https://dx.doi.org/10.1063/5.0079989 0003-6951 https://hdl.handle.net/10356/157912 10.1063/5.0079989 16 120 161104 en NRF-CRP23-2019-0005 NAP-SUG A18A6b0057 MOE2019-T2-1-058 Applied Physics Letters 10.21979/N9/WJDQAH © 2022 Author(s). All rights reserved. This paper was published by AIP Publishing in Applied Physics Letters and is made available with permission of Author(s). application/pdf application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic Science::Physics::Optics and light
spintronic terahertz Emission
Terahertz Hysteresis
Terahertz Charge Current
Terahertz Magnetometer
THz-H Hysteresis
spellingShingle Science::Physics::Optics and light
spintronic terahertz Emission
Terahertz Hysteresis
Terahertz Charge Current
Terahertz Magnetometer
THz-H Hysteresis
Agarwal, Piyush
Yang, Yingshu
Lourembam, James
Medwal, Rohit
Battiato, Marco
Singh, Ranjan
Terahertz spintronic magnetometer (TSM)
description A ferromagnetic metal consists of localized electrons and conduction electrons coupled through strong exchange interaction. Together, these localized electrons contribute to the magnetization of the system, while conduction electrons lead to the formation of spin and charge current. Femtosecond out of equilibrium photoexcitation of ferromagnetic thin films generates a transient spin current at ultrafast timescales that have opened a route to probe magnetism offered by the conduction electrons. In the presence of a neighboring heavy metal layer, the non-equilibrium spin current is converted into a pulsed charge current and gives rise to terahertz (THz) emission. Here, we propose and demonstrate a tool known as the terahertz spintronic magnetometry. The hysteresis loop obtained by sweeping terahertz (THz) pulse amplitude as a function of the magnetic field is in excellent agreement with the vibrating-sample magnetometer measurements. Furthermore, a modified transfer-matrix method employed to model the THz propagation within the heterostructure theoretically elucidates a linear relationship between the THz pulse amplitude and sample magnetization. The strong correlation, thus, reveals spintronic terahertz emission as an ultrafast magnetometry tool with reliable in-plane magnetization detection, highlighting its technological importance in the characterization of ferromagnetic thin-films through terahertz spintronic emission spectroscopy.
author2 School of Physical and Mathematical Sciences
author_facet School of Physical and Mathematical Sciences
Agarwal, Piyush
Yang, Yingshu
Lourembam, James
Medwal, Rohit
Battiato, Marco
Singh, Ranjan
format Article
author Agarwal, Piyush
Yang, Yingshu
Lourembam, James
Medwal, Rohit
Battiato, Marco
Singh, Ranjan
author_sort Agarwal, Piyush
title Terahertz spintronic magnetometer (TSM)
title_short Terahertz spintronic magnetometer (TSM)
title_full Terahertz spintronic magnetometer (TSM)
title_fullStr Terahertz spintronic magnetometer (TSM)
title_full_unstemmed Terahertz spintronic magnetometer (TSM)
title_sort terahertz spintronic magnetometer (tsm)
publishDate 2022
url https://hdl.handle.net/10356/157912
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