Antiferromagnetic Tunnel Junction as a Detector of Terahertz Frequency Signals

Although terahertz-frequency (TF) electromagnetic radiation has a great potential in medical, security, industry and science applications, nowadays there are great challenges in the generation, detection and processing of quasi-monochromatic TF electromagnetic signals. In this paper we present a novel type of dc biased TF signal detector (TFD) based on an antiferromagnetic tunnel junction (ATJ) that consists of two outer platinum layers and the inner antiferromagnet / MgO bilayer. In such a detector an output dc voltage is generated across the ATJ, when quasi-monochromatic TF signal with frequency equal to the frequency of dc current-driven magnetization oscillations in the antiferromagnetic layer is applied. Using a simple electric scheme of the TFD we show that although detector's output voltage reduces with an increase of frequency, it can reach 0.4 mV for input power of 1 μW in the frequency range 0.1 - 1 THz if the ATJ with thin MgO tunneling barrier (~ 1 nm) and small lateral size (~ 100 nm) is used.