Spin current propagation through epitaxial antiferromagnetic thin films
Lead Research Organisation:
Diamond Light Source
Department Name: CEO's Office
Abstract
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Organisations
Publications
Burn DM
(2023)
Spin pumping through nanocrystalline topological insulators.
in Nanotechnology
Newman D
(2024)
Influence of an ultrathin Mn 'spy layer' on the static and dynamic magnetic coupling within FePt/NiFe bilayers
in Journal of Physics D: Applied Physics
Sait C
(2024)
Unidirectional multipulse helicity-independent all-optical switching in [Ni/Pt] based synthetic ferrimagnets
in Physical Review B
| Description | Unidirectional Multi-Pulse Helicity-Independent All-Optical Switching in [Ni/Pt] Based Synthetic Ferrimagnets. Paper submitted to PRB, currently under review |
| Exploitation Route | Nickel-platinum based synthetic ferrimagnets (SFi's) are highly tunable and rare-earth-free materials that allow ultrafast all optical control of magnetism to be explored. This study considers a SFi composed of a ferromagnetic [Ni/Pt] multilayer and a ferromagnetic Co layer, separated by an Ir layer that mediates an antiferromagnetic coupling. Helicity-independent all optical switching (HI-AOS) between two antiparallel magnetization states is observed. AOS may be realized at increased temperature through reduction of the thickness of the Pt layers. Switching is unidirectional and has a strong dependence on the applied magnetic field history that points to the importance of nanoscale magnetic texture in controlling AOS in SFi systems. |
| Sectors | Digital/Communication/Information Technologies (including Software) Electronics Energy Environment |
| Description | The goal of this research was to deepen our understanding of spin wave propagation in antiferromagnetic (AFM) materials, particularly NiO and CoO, with the aim of advancing low-power, high-speed spintronic devices. By optimizing spin current transmission and amplification, this work contributes to the development of spin-torque RAM (ST-RAM), offering the potential for faster, more energy-efficient memory technologies. Given that AFM materials operate at terahertz (THz) frequencies, our findings also have significant implications for THz signal processing. These insights could be leveraged by companies such as Seagate, Western Digital, and semiconductor firms exploring AFM materials for data storage and computing applications. Through x-ray ferromagnetic resonance (XFMR) experiments, we demonstrated that spin current in NiO is predominantly carried by GHz-frequency evanescent spin waves, rather than previously assumed THz-frequency thermal magnons. Our findings revealed that spin current transmission peaked at a 6 nm NiO thickness, then declined in a manner consistent with evanescent wave decay. Even when a nonmagnetic spacer (Ag or Pd) was introduced to disrupt interfacial exchange coupling, spin current transmission persisted, confirming the role of coherent spin waves in spin transport. Moreover, we identified conditions under which spin current amplification occurs, suggesting that NiO could serve as an active medium for enhancing spin transport. Our results validate theoretical models of spin current transport in AFMs and reinforce the feasibility of using AFM materials for energy-efficient spintronic devices. The potential for spin current amplification could lead to significant reductions in energy consumption for data centres and embedded computing, aligning with global initiatives to develop sustainable, low-power computing solutions. Our findings establish a foundation for future advancements in AFM-based spintronics, paving the way for next-generation memory, computing, and signal processing technologies. |
| First Year Of Impact | 2023 |
| Sector | Digital/Communication/Information Technologies (including Software),Education,Electronics,Energy,Environment |
| Impact Types | Economic |