Antiferromagnetic–ferromagnetic heterostructure-based spin Hall nano-oscillator

• Published in: Applied physics letters 2024-11, Vol.125 (19)
• Main Authors: Soni, Sandeep, Raj, Ravish Kumar, Kaushik, Brajesh Kumar
• Format: Article
• Language: English
• Subjects: Antiferromagnetism; Dynamic characteristics; Electrons; Ferromagnetic materials; Frequency ranges; Heterostructures; Oscillators; Power management; Spin dynamics; Stable oscillations; Temperature effects
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/5.0231305

Spin oscillators relying on ferromagnetic (FM) materials have been limited to frequency generation in the range of only a few gigahertz. In contrast, antiferromagnetic (AFM) material-based oscillators have a potential for beyond gigahertz range oscillations. However, the use of AFM oscillators is limited due to challenges in detecting and controlling magnetic orientation. This arises from the inherent lack of significant net magnetization in AFMs. This work focuses on exploring the dynamic characteristics of a spin Hall nano-oscillator (SHNO) that addresses these challenges by leveraging the inter-layer exchange interaction between AFM and FM layers. The proposed design demonstrates stable and power-efficient oscillation in the FM layer, relying on the dynamics of the AFM layer. The proposed AFM–FM-based SHNO design achieves a maximum frequency of 16.4 GHz at ISOT = 180 μA. Furthermore, considering the thermal effects at 300 K, the stable oscillation frequency is achieved at 15.94 GHz. The proposed device exhibits robust and tunable oscillations over a wide frequency range with a power consumption of 4 μW. Moreover, this oscillator achieves 3.35× and 2.44× higher oscillation frequency compared to spin torque nano-oscillators and conventional SHNO-based oscillators, respectively.