Infrared photo-response of Fe-shunted Ba-122 thin film microstructures

TL;DR

This study investigates the infrared photo-response of Fe-shunted Ba-122 thin film microstructures, revealing substrate-dependent electron energy relaxation times and demonstrating their potential for infrared detection applications.

Contribution

It provides new insights into the infrared photo-response behavior of Fe-shunted Ba-122 microstructures and highlights the influence of substrate material on electron energy relaxation.

Findings

Electron energy relaxation is faster on MgAl2O4 substrates.

Microbridges exhibit Tc up to 20 K and critical current density up to 2.56 MA/cm2.

Photo-response varies with incident power, temperature, and bias current.

Abstract

We present a study of the response to pulsed infrared radiation of Fe-layer shunted pnictide thin film microstructures. The thin film multilayer consisting of 20 nm thick Fe-buffer, 50 nm thick Ba(Fe,Co)2As2 film and gold protection layer were deposited on heated MgO and MgAl2O4 substrates by pulsed-laser deposition. The multilayers were patterned into 5 to 8 um wide and 5 um long microbridges by electron-beam lithography and ion-milling technique. The microbridges show Tc up to 20 K and a critical current density up to 2.56 MA/cm2 at T = 10 K. The photo-response of Fe-shunted Ba(Fe,Co)2As2 thin film microbridges to infrared radiation was studied in a wide range of incident optical power, operation temperature and bias current. We have found that the electron energy relaxation in studied multilayers is dependent on substrate material and is 1.75 times faster in case of MgAl2O4 characterized by lattice matching to pnictide film in comparison to MgO substrate.