Spintronic based RF components
Ursula Ebels (Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP*, INAC, SPINTEC, F-38000, Grenoble, France; * Institute of Engineering Univ. Grenoble Alpes)

Spintronics has been an important driver for Information Technologies (IT) in the last two decades by exploiting the spin degree of freedom in ferromagnetic heterostructures. The introduction in 1996 of magneto-resistive field sensors as read heads led to a dramatic increase in digital data storage density. A similar impact is predicted for magnetic random access memories. With the recent evolution of interconnected devices and objects, the Internet of Things (IoT), not only sensing, storing and processing information (functions that can all be realized by spintronics devices), but also communication of data is an essential aspect. This is driving wireless communication technologies, to find solutions for low power, cost effective, compact rf components and systems. Spintronics might offer here alternative solutions that result from the spin angular momentum. Like a spinning top the magnetization precesses around its equilibrium axis when perturbed by external forces (torques). Combing these spinning-top-properties with spin polarized transport properties (spin momentum transfer and magneto-resistance) this defines active, compact and multifunctional rf components.

Injection of a spin polarized DC current leads to a steady state magnetization precession at large amplitudes that is converted via the magneto-resistance into a rf voltage signal. This defines a nano-scale microwave signal source. Besides this DC-to-RF converter function, spintronic devices can offer a large range of other functionalities. Upon simultaneous application of a DC current (to generate the signal) and an rf current, the output signal can be either modulated and used to decode/encode information or it can be injection locked to an external source. Furthermore, the inverse RF-to-DC converter function has been demonstrated. Here the injected rf current is rectified providing a DC output signal which defines a frequency selective microwave signal detector.

In this presentation, the different rf functions of spintronics devices will be presented and their state of the art performances will be described for standalone devices, for coupled devices as well as for first system level developments.