Enhanced laser-induced single-cycle terahertz generation in a spintronic emitter with a gradient interface
The development of spintronic emitters of broadband terahertz (THz) pulses relies on designing heterostructures in which the processes of laser-driven spin current generation and subsequent spin-to-charge current conversion are the most efficient. The interface between the ferromagnetic and nonmagne...
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| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Taylor & Francis Group
2025-12-01
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| Series: | Science and Technology of Advanced Materials |
| Subjects: | |
| Online Access: | https://www.tandfonline.com/doi/10.1080/14686996.2024.2448417 |
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| Summary: | The development of spintronic emitters of broadband terahertz (THz) pulses relies on designing heterostructures in which the processes of laser-driven spin current generation and subsequent spin-to-charge current conversion are the most efficient. The interface between the ferromagnetic and nonmagnetic layers in an emitter is a critical element. In this study, we experimentally examined single-cycle THz pulse generation from a laser-pulse-excited Pt/Co emitter with a 1.2-nm-thick composition-gradient interface between the Pt and Co and compared it with the emission from a conventional Pt/Co structure with an abrupt interface. We found that the gradient interface improved the efficiency of the optics-to-THz conversion by a factor of two in a wide range of optical fluences up to 3 mJ⋅cm−2. This enhancement was caused by a pronounced increase in the transmittance of the laser-driven spin-polarized current through the gradient interface compared with the abrupt interface. Moreover, it was evident that such transmission deteriorated with the laser fluence owing to the spin accumulation effect. |
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| ISSN: | 1468-6996 1878-5514 |