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MA: Fachverband Magnetismus

MA 41: Poster III

MA 41.1: Poster

Donnerstag, 20. März 2025, 15:00–17:30, P3

Electrical coupling of superparamagnetic tunnel junctions mediated by spin-transfer-torques — •Sinan Shu¹, Leo Schnitzspan^{1, 2}, Mathias Kläui^{1, 2}, and Gerhard Jakob^{1, 2} — ¹Institute of Physics, Johannes Gutenberg-University Mainz, 55122 Mainz, Germany — ²Max Planck Graduate Center Mainz, 55122 Mainz, Germany

Superparamagnetic tunnel junctions (SMTJs) have garnered significant interest as potential building blocks for neuromorphic computing due to their unique stochastic switching behavior, driven by thermal excitations. This work investigates the impact of electrical coupling on the stochastic dynamics of two in-plane magnetized SMTJs, combining experimental measurements with simulation studies. The coupling mechanism, enabled by spin-transfer torque, modulates the state probability of each SMTJ and influences their cross-correlation. By analyzing time-lagged cross-correlation, we determine the strength and direction of the coupling, revealing that high positive voltages induce the strongest coupling effect. Furthermore, we demonstrate voltage-tunable state probabilities and coupling control. Our findings highlight the emergence of similarity and dissimilarity effects in the state probability transfer curves of coupled SMTJs [1]. These results not only provide new insights into the interplay between spin-transfer torque and stochastic behavior but also underline the potential of SMTJs for applications in energy-efficient neuromorphic computing.

[1] L. Schnitzspan, M. Kläui, G. Jakob, Appl. Phys. Lett. 123, 232403 (2023).

Keywords: Spin-transfer-torque; Magnetic tunnel junctions; Stochastic processes; Nonvolatile random-access memory; Nanomagnets