Influence of Temperature on the Noise-Handling Properties of a Sub-Terahertz Detector Based on an Antiferromagnetic Tunnel Junction

In this paper we numerically analyze the performance of a subterahertz frequency signal detector based on an antiferromagnetic tunnel junction (AT J) in the presence of thermal noise. The detector is a four-layer AT J
$\mathbf{P t} / \text{Ir}_{0.2} \text{Mn}_{0.8} / \mathbf{M g O} / \mathbf{P t}$
connected to an external circuit of
$50\Omega$
impedance and operating based on the anisotropic tunneling magnetoresistance (ATMR) effect. Using the detector model, where the detector is considered as an equivalent RLC-circuit, and assuming that MgO tunneling barrier thickness, ATMR ratio, and AT J resistance-area product are the temperature-dependent values, we calculate the temperature dependences
$(T=4.2-300\mathrm{K})$
of the detector output DC voltage
$U_{\text{DC}}(T)$
and its signal-to-noise ratio SNR(1) in the presence of low-frequency Johnson-Nyquist noise. Our results indicate that although the dependence
$U_{\text{DC}}(T)$
is relatively weak (temperature-dependent changes of UDC are less than
$\pm 3\%$
), the SNR(1) substantially increases with a decrease of temperature
$T$
,, and for an AT J with optimal parameters at cryogenic temperatures ~ 10 K, it can reach ~ 500. The obtained results can be useful for the development and optimization of spintronic detectors based on antiferromagnetic nanostructures.