Stochastic Nature of Voltage-Controlled Charge Dynamics in AlOx Magnetic Tunnel Junctions

Ch.Y. Chen, B.H. Huang, Y.H. Tang, C. González-Ruano, F. Aliev Kazanski, D.Ch. Ling, J.Y. Hong

Nano Letters Vol. 25, nº. 31, pp. 11776 - 11781

Resumen:

Spintronic memristors based on ferromagnetic metal/oxide heterostructures have recently enabled reversible manipulation of both magnetic properties and resistive switching (RS), offering promising prospects for multibit memory and neuromorphic computing. In this study, we investigate the stochastic nature and relaxation processes of charge dynamics induced by localized oxygen vacancy (V_O) in AlO_x-based magnetic tunnel junctions (MTJs). We observe that random telegraph noise (RTN) exhibits charge stochasticity at specific bias voltages in the low resistance state (LRS), reflecting the competition and transition between charge capture and emission states against the thermal energy. This behavior reveals that the thermally unstable charge stochasticity originates from localized traps in the AlO_x barrier. In contrast, the high resistance state (HRS) favors the RTN emission states, indicating the dominance of direct tunneling effects. Through numerical calculations based on the tight-binding (TB) model and experimental results, we demonstrate that voltage-driven shifts in the V_O position within the AlO_x barrier, associated with RS, govern the charge dynamics of the MTJs investigated. These findings provide valuable insights and practical implications for the development of next-generation devices leveraging charge stochasticity in AlO_x-based MTJs.

Resumen divulgativo:

Las memorias magnéticas ofrecen un gran potencial para la computación. Aquí estudiamos el comportamiento de uniones túnel basadas en AlO_x. Presentan dos estados en función del voltaje y el campo magnético, que podrían ser útiles para los dispositivos informáticos de próxima generación.

Palabras Clave: magnetic tunnel junction; memristor; resistive switching; random telegraph noise; oxygen vacancy

Índice de impacto JCR-JIF y cuartil WoS: 9,100 - Q1 (2025)

Referencia DOI: https://doi.org/10.1021/acs.nanolett.5c01332

Publicado en papel: Agosto 2025.

Publicado on-line: Julio 2025.

Cita:
Ch.Y. Chen, B.H. Huang, Y.H. Tang, C. González-Ruano, F. Aliev Kazanski, D.Ch. Ling, J.Y. Hong, "Stochastic Nature of Voltage-Controlled Charge Dynamics in AlOx Magnetic Tunnel Junctions", Nano Letters, Vol. 25, nº. 31, pp. 11776 - 11781, Agosto 2025. [Online: Julio 2025] doi: 10.1021/acs.nanolett.5c01332