Department of Circuit Design and Network Theory, Technische Universität Dresden, Dresden, Germany, Unité Mixte de Physique CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau, France, CEA, INAC-SPINTEC, CNRS, SPINTEC, University Grenoble Alpes, Grenoble, France, International Iberian Nanotechnology Laboratory (INL), Braga, Portugal, CEA-LETI MINATEC-CAMPUS, University Grenoble Alpes, Grenoble, France

Spin-torque nano-oscillators (STO) are candidates for the next technological implementation of spintronic devices in commercial electronic systems. For use in microwave applications, improving the noise figures by efficient control of their phase dynamics is a mandatory requirement. In order to achieve this, we developed a compact phase locked loop (PLL) based on custom integrated circuits (ICs) and demonstrate that it represents an efficient way to reduce the phase noise level of a vortex based STO. The advantage of our approach to phase stabilize STOs is that our compact system is highly reconfigurable e.g. in terms of the frequency divider ratio N, RF gain and loop gain. This makes it robust against device to device variations and at the same time compatible with a large range of STOs. Moreover, by taking advantage of the natural highly non-isochronous nature of the STO, the STO frequency can be easily controlled by e.g. changing the divider ratio N. © 2017 Author(s).

Integrated circuits, Locks (fasteners), Phase locked loops, Phase noise, Timing circuits, Vortex flow, Commercial electronic systems, Frequency dividers, Mandatory requirement, Microwave applications, Phase Locked Loop (PLL), Phase-noise levels, Spin-torque oscillators, Spintronic device, Oscillators (electronic)