Broad-energy oxygen ion implantation controlled magnetization dynamics in CoFeTaZr
In this paper, a novel pulsed broad energy spectrum ion-implantation technique, using the dense plasma focus device (DPF), for uniform oxygen-ion doping along the thickness of a ~250 nm thick magnetic CoFeTaZr layer is investigated. A new operational regime of the dense plasma focus – the off-focus...
| Main Authors: | , , , , , , , , |
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| Format: | Journal Article |
| Language: | English |
| Published: |
2023
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| Online Access: | https://hdl.handle.net/10356/167879 |
| _version_ | 1811692314653884416 |
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| author | Vas, Joseph Vimal Medwal, Rohit Chaudhuri, Ushnish Mishra, Mayank Chaurasiya, Avinash Mahendiran, Ramanathan Piramanayagam, S. N. Rawat, Rajdeep Singh Lee, Paul Choon Keat |
| author2 | School of Physical and Mathematical Sciences |
| author_facet | School of Physical and Mathematical Sciences Vas, Joseph Vimal Medwal, Rohit Chaudhuri, Ushnish Mishra, Mayank Chaurasiya, Avinash Mahendiran, Ramanathan Piramanayagam, S. N. Rawat, Rajdeep Singh Lee, Paul Choon Keat |
| author_sort | Vas, Joseph Vimal |
| collection | NTU |
| description | In this paper, a novel pulsed broad energy spectrum ion-implantation technique, using the dense plasma focus device (DPF), for uniform oxygen-ion doping along the thickness of a ~250 nm thick magnetic CoFeTaZr layer is investigated. A new operational regime of the dense plasma focus – the off-focus mode – is explored to avoid the surface damage of the exposed sample by the high energy plasma streams/jets and instability accelerated ions, typically observed in conventional efficient-focus mode operation. The faraday cup measurements shows the increase in ion fluence from 3.83 × 1013 ion/cm2 for efficient-focus mode to 8.76 × 1013 ion/cm2 for off-focused mode operation in the broad-ion-energy range of 1–100 keV. The x-ray photoelectron spectroscopy (XPS) of the unexposed sample shows the presence of Co in Co0, Co2+ and Co3+, Fe in Fe0, Fe2+ and Fe3+, and Ta in Ta0 and Ta2+ oxidation states while Zr was observed with only metallic Zr binding energy peaks indicating the surface oxidation of the unexposed sample. The exposure to oxygen plasma in DPF device led to the increase in the higher oxidation states of Co, Fe and Ta with reduction in metallic binding energy peak and the deconvolution of oxygen XPS spectrum confirmed the bonding of oxygen to Co, Fe and Ta. The magnetization dynamics of unexposed and oxygen-ion doped samples was studied using magnetoimpedance measurements in the 1–2.5 GHz frequency range. Gilbert’s damping factor, in-plane anisotropy and effective magnetization of the magnetic substrate were calculated and it is found that these properties can be modulated with a lighter ion dosage using this novel pulsed broad-energy-ion implantation technique. It is concluded that the off-focus mode DPF operation can provide the ions of required energy and fluence to implant oxygen ions across the thickness of the CoFeTaZr magnetic thin film to modulate its magnetic properties. |
| first_indexed | 2024-10-01T06:33:49Z |
| format | Journal Article |
| id | ntu-10356/167879 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T06:33:49Z |
| publishDate | 2023 |
| record_format | dspace |
| spelling | ntu-10356/1678792023-06-21T07:24:42Z Broad-energy oxygen ion implantation controlled magnetization dynamics in CoFeTaZr Vas, Joseph Vimal Medwal, Rohit Chaudhuri, Ushnish Mishra, Mayank Chaurasiya, Avinash Mahendiran, Ramanathan Piramanayagam, S. N. Rawat, Rajdeep Singh Lee, Paul Choon Keat School of Physical and Mathematical Sciences National Institute of Education Science::Physics Ion Implantation Magnetization Dynamics In this paper, a novel pulsed broad energy spectrum ion-implantation technique, using the dense plasma focus device (DPF), for uniform oxygen-ion doping along the thickness of a ~250 nm thick magnetic CoFeTaZr layer is investigated. A new operational regime of the dense plasma focus – the off-focus mode – is explored to avoid the surface damage of the exposed sample by the high energy plasma streams/jets and instability accelerated ions, typically observed in conventional efficient-focus mode operation. The faraday cup measurements shows the increase in ion fluence from 3.83 × 1013 ion/cm2 for efficient-focus mode to 8.76 × 1013 ion/cm2 for off-focused mode operation in the broad-ion-energy range of 1–100 keV. The x-ray photoelectron spectroscopy (XPS) of the unexposed sample shows the presence of Co in Co0, Co2+ and Co3+, Fe in Fe0, Fe2+ and Fe3+, and Ta in Ta0 and Ta2+ oxidation states while Zr was observed with only metallic Zr binding energy peaks indicating the surface oxidation of the unexposed sample. The exposure to oxygen plasma in DPF device led to the increase in the higher oxidation states of Co, Fe and Ta with reduction in metallic binding energy peak and the deconvolution of oxygen XPS spectrum confirmed the bonding of oxygen to Co, Fe and Ta. The magnetization dynamics of unexposed and oxygen-ion doped samples was studied using magnetoimpedance measurements in the 1–2.5 GHz frequency range. Gilbert’s damping factor, in-plane anisotropy and effective magnetization of the magnetic substrate were calculated and it is found that these properties can be modulated with a lighter ion dosage using this novel pulsed broad-energy-ion implantation technique. It is concluded that the off-focus mode DPF operation can provide the ions of required energy and fluence to implant oxygen ions across the thickness of the CoFeTaZr magnetic thin film to modulate its magnetic properties. Ministry of Education (MOE) National Research Foundation (NRF) This research is supported by the Ministry of Education (MOE) under its Academic Research Fund Tier 1 (2018-T1-001-107), if applicable. R. Mahendiran acknowledges MOE, Singapore for support (Grant no.s R144-000-381-112 and R114-000-442-114). R. S. Rawat acknowledges MOE, Singapore for the support through MOE Tier 2 Grant, ARC-1/17 RSR (MOE2017-T2-2-129) and NRF, Singapore for the support through CRP Grant, CRP21-2018-0093. 2023-05-23T05:00:47Z 2023-05-23T05:00:47Z 2021 Journal Article Vas, J. V., Medwal, R., Chaudhuri, U., Mishra, M., Chaurasiya, A., Mahendiran, R., Piramanayagam, S. N., Rawat, R. S. & Lee, P. C. K. (2021). Broad-energy oxygen ion implantation controlled magnetization dynamics in CoFeTaZr. Journal of Alloys and Compounds, 872, 159685-. https://dx.doi.org/10.1016/j.jallcom.2021.159685 0925-8388 https://hdl.handle.net/10356/167879 10.1016/j.jallcom.2021.159685 872 159685 en NRF-CRP21-2018-0093 2018-T1-001-107 R144-000-381-112 R114-000-442-114 MOE2017-T2-2-129 Journal of Alloys and Compounds © 2021 Elsevier B.V. All rights reserved. |
| spellingShingle | Science::Physics Ion Implantation Magnetization Dynamics Vas, Joseph Vimal Medwal, Rohit Chaudhuri, Ushnish Mishra, Mayank Chaurasiya, Avinash Mahendiran, Ramanathan Piramanayagam, S. N. Rawat, Rajdeep Singh Lee, Paul Choon Keat Broad-energy oxygen ion implantation controlled magnetization dynamics in CoFeTaZr |
| title | Broad-energy oxygen ion implantation controlled magnetization dynamics in CoFeTaZr |
| title_full | Broad-energy oxygen ion implantation controlled magnetization dynamics in CoFeTaZr |
| title_fullStr | Broad-energy oxygen ion implantation controlled magnetization dynamics in CoFeTaZr |
| title_full_unstemmed | Broad-energy oxygen ion implantation controlled magnetization dynamics in CoFeTaZr |
| title_short | Broad-energy oxygen ion implantation controlled magnetization dynamics in CoFeTaZr |
| title_sort | broad energy oxygen ion implantation controlled magnetization dynamics in cofetazr |
| topic | Science::Physics Ion Implantation Magnetization Dynamics |
| url | https://hdl.handle.net/10356/167879 |
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