Researchers develop ‘world's most powerful’ nanoscale microwave oscillators

While current oscillators are silicon-based and use the charge of an electron to create microwaves, the UCLA developed oscillators, utilise the spin of an electron, as in the case of magnetism, and are said to carry several orders of magnitude advantages over the oscillators commonly in use today. The devices grew out of research at the UCLA Henry Samueli School of Engineering and Applied Science, which focused on STT-RAM, or spin-transfer torque magnetoresistive random access memory, which has great potential over other types of memory in terms of both speed and power efficiency. "We realised that the layered nanoscale structures that make STT-RAM such a great candidate for memory could also be developed for microwave oscillators for communications," said principal investigator Professor Kang Wang. The structures, called spin-transfer nano-oscillators, or STNOs, are composed of two distinct magnetic layers. One layer has a fixed magnetic polar direction, while the other layer's magnetic direction can be manipulated to gyrate by passing an electric current through it. This allows the structure to produce very precise oscillating microwaves. "Previously, there had been no demonstration of a spin transfer oscillator with sufficiently high output power and simultaneously good signal quality, which are the two main metrics of an oscillator – hence preventing practical applications," Prof Wang noted. "We have realised both these requirements in a single structure."