Spin-injection terahertz radiation in magnetic junctions

TL;DR

This paper reports room-temperature terahertz radiation generated by spin injection in magnetic junctions, with power exceeding thermal background and directly following the current, indicating potential for spintronic terahertz sources.

Contribution

It demonstrates a novel spin-injection mechanism producing terahertz radiation in magnetic junctions at room temperature, with significant power output.

Findings

Terahertz radiation observed at 1-10 THz range

Radiation power exceeds thermal background

Radiation directly follows electric current

Abstract

Electromagnetic radiation of 1 - 10 THz range has been found at room temperature in a structure with a point contact between a ferromagnetic rod and a thin ferromagnetic film under electric current of high enough density. The radiation is due to nonequilibrium spin injection between the structure components. By estimates, the injection can lead to inverted population of the spin subbands. The radiation power exceeds by orders of magnitude the thermal background (with the Joule heating taking into account) and follows the current without inertia.