Novel spin-based logic architectures, based on vertical magnetic multilayers, are being developed to provide high-performance nonvolatile data retention and processing. As a counterpart to the vertical stacks, we have recently developed two new lateral couplings based on (i) the Dzyaloshinskii–Moriya interaction (DMI) in systems with non-uniform anisotropy [1] and (ii) on the exchange interaction in ferrimagnetic films [2], which significantly boost the possibility to design novel planar magnetic circuits.
​ The first concept exploits the chiral coupling mechanism between adjacent magnets where the non-collinear magnetic anisotropy competes with the interfacial DMI in Pt/Co/AlOx trilayers [3, 4]. When an in-plane (IP) magnetized region is fabricated next to an out-of-plane (OOP) magnetized region, the adjacent magnetic moments are coupled in a chiral manner. The chiral IP-OOP structure can be implemented in a domain wall inverter, the essential building block for all implementations of Boolean logic. Based on this principle, we realized reconfigurable NAND and NOR logic gates, making our concept for current-driven DW logic functionally complete [5-7]. The second coupling makes use of the strong lateral coupling mechanism in a single GdCo ferrimagnetic layer relying on the exchange interaction [2]. This interaction is achieved by spatially patterning the compensation temperature of the ferrimagnet. We have shown that the strength of the interaction can be manipulated by tuning the geometrical parameters.
​ The generation of these powerful coupling mechanism is, however, limited to a very narrow family of materials. To overcome this bottleneck, we have developed a novel method to pattern arbitrary magnetic landscapes based on local laser annealing. The underlying magnetic properties are linked to heat-activated processes such as crystallization, alloying or oxidation. We demonstrate how this method opens the way to create landscapes with grayscale capability with unprecedented applications in chiral spintronics and beyond [8].
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​ [1] Luo, Z. et al. Science 363, 1435 (2019).
​ Liu, Z. et al. Phys. Rev. B 107, L100412 (2023).
​ Hrabec, A. et al. Appl. Phys. Lett. 115, 130503 (2020).
​ Liu, Z. et al. Phys. Rev. Appl. 16, 054049 (2021).
​ Luo, Z. et al. Nature 579, 214-218 (2020).
​ Luo Z. et al. Phys. Rev. Appl. 15, 034077 (2021).v Zeng Z. et al. Appl. Phys. Lett. 118, 222405 (2021).v Riddiford L, Brock, J. A.. et al. arXiv:2401.09314 (2024).
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More information :https://www.spintec.fr/seminar-realization-of-magnetic-circuits-exploiting-lateral-couplings/​

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