MRAM: from STT to SOT, for security and memory

Kharbouche-Harrari, M.; Alhalabi, Rana; Postel-Pellerin, J.; Wacquez, R.; Aboulkassimi, Driss; Nowak, E.; Prejbeanu, I. L.; Prenat, Guillaume; Pendina, Grégory Di

doi:10.1109/dcis.2018.8681468

Cited by 4 publications

(2 citation statements)

References 15 publications

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“…AGNETIC Random Access Memory (MRAM) has been developed in several generations so far, in particular STT-MRAM which is one of the most attractive emerging memories candidates [1,2]. For high-density STT-MRAM integration, perpendicular magnetic tunnel junctions (p-MTJs) are more energy efficient due to stronger perpendicular anisotropy and reduced energy levels needed to perform switching are expected to achieve lower critical current density and greater thermal stability, thus lower bias voltage.…”

Section: Introductionmentioning

confidence: 99%

Real-Time Switching Dynamics in STT-MRAM

Yazigy

Postel-Pellerin

Marca

et al. 2022

IEEE J. Electron Devices Soc.

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In this paper a new experimental technique for measuring the switching dynamics and extracting the energy consumption of Spin Transfer Torque MRAM (STT-MRAM) device is presented. This technique is performed by a real-time current reading while a pulsed bias is applied. The switching from a high resistive state, anti-parallel (AP) alignment, to a low resistive state, parallel (P) alignment, is investigated as well as the impact of the cell diameter on the switching parameters. We demonstrate that preswitching and switching times and energies have a log-linear relationship with the applied voltage. Increasing the applied voltage leads to a higher spin torque on the free layer in a shorter time. This decreases the time needed to change the magnetization orientation of this layer, thus the time required before the switching occurs. We have also shown that for a given applied voltage, the smaller the cell the longer the time before switching. For low applied voltages, the preswitching time increases exponentially dominating the whole reversal time. The longer switching times can be explained by a lower Joule heating not sufficient to induce the thermally activated reversal process. This phenomenon is accentuated for smaller cells, where the heating is more significant and the time before switching is shorter than for larger cells.

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Section: Introductionmentioning

confidence: 99%

Real-Time Switching Dynamics in STT-MRAM

Yazigy

Postel-Pellerin

Marca

et al. 2022

IEEE J. Electron Devices Soc.

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“…The presence of Dirac points in their band structure endows TIs with exceptional surface conductivity, − making them versatile candidates for applications in various fields, including quantum computing, topological photonics, energy-efficient electronics, and more importantly, in the field of spintronics. , The importance of TIs to spintronics lies in their properties to enable efficient spin transport, manipulation, and detection, which is fundamental to the development of advanced spin-based devices with notable energy efficiency, enhanced performance, and functionality . Within the realm of spintronics, the emergence of spin–orbit torque magnetic random access memories (SOT-MRAMs) and SOT readers beyond 4 Tb/in 2 magnetic recording technology has garnered extensive attention for its potential as an energy-efficient solution for neuromorphic computing and data storage. − In SOT-based devices, the most important layer is the spin Hall layer, which converts charge current to spin current through a phenomenon known as the spin Hall effect (SHE) and vice versa, i.e., spin flow is converted to charge current through the inverse spin Hall effect (ISHE). ,, Beyond conventional heavy metals, , some of the topological materials have been studied as spin-to-charge conversion systems in the SOT devices, such as BiSb, , Bi 2 Se 3 , − and Bi 2 Te 3 , which exhibit high spin Hall angles (SHAs) or SOT efficiencies due to their strong spin–orbit coupling and topological electronic structures.…”

Section: Introductionmentioning

confidence: 99%

Spin–Orbit Torque Modulated by Interface Chemistry in Topological BiSb/NiFe Bilayers with Titanium Insertion

Manoj,

Wen,

Uzuhashi

et al. 2024

ACS Appl. Electron. Mater.

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Topological insulators are intriguing materials in the field of spintronics because they exhibit unique electronic properties that hold great promise for device applications. BiSb has attracted more research interest among topological materials due to its remarkably high spin−orbit torque (SOT) efficiency. However, due to the low melting point of the alloy, high diffusivities of Bi/Sb tend to degrade the SOT efficiency with temperature and aging. In this work, we utilize interfacial chemistry driven by a titanium (Ti) spacer between BiSb and NiFe bilayers to improve the SOT efficiency. We investigated the effect of the Ti insertion layer on the SOT efficiency under as-deposited, room-temperature aging, and annealing conditions. The SOT efficiency, estimated from the spin-torque ferromagnetic resonance response, revealed that the samples with the Ti layer had shown a multifold increase in the SOT efficiency compared to those without Ti insertion. Atomic resolution microstructural analyses provided a clear understanding of the interfacial chemistry where Ti successfully hindered the interdiffusion of Ni and Sb. The interfacial chemistry in the vicinity of Ti contributed significantly to the improvement of the SOT efficiency. These results highlight the importance of the Ti insertion layer in the BiSb-based topological material/ferromagnet bilayer systems for SOT applications in spintronics.

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