Coherent interfacial bonding on the FeAs tetrahedron in Fe/Ba(Fe(1-x)Co(x))2As2 bilayers

TL;DR

This paper reports the successful growth of epitaxial Fe/Ba(Fe(1-x)Co(x))2As2 bilayers with coherent interfacial bonding, demonstrating potential for superconducting/ferromagnetic heterostructures using Pulsed Laser Deposition.

Contribution

It introduces a method to create epitaxial Fe/Ba-122 bilayers with coherent interfaces, advancing fabrication techniques for iron pnictide heterostructures.

Findings

Achieved epitaxial growth on MgO and LSAT substrates.

Observed coherent interfacial bonding via atomic resolution microscopy.

Superconducting transition temperatures close to target values.

Abstract

We demonstrate the growth of epitaxial Fe/Ba(Fe(1-x)Co(x))2As2 (Fe/Ba-122) bilayers on MgO(001) and LSAT(001) single crystal substrates using Pulsed Laser Deposition (PLD). By exploiting the metallic nature of the FeAs tetrahedron in the Ba-122 crystal structure, we achieve a coherent interfacial bond between bcc iron and Co-doped Ba-122. Tc values for both bilayers were close to that of the PLD target. Direct observation of interfacial bonding between Fe and the Ba-122 FeAs sublattice by atomic resolution transmission electron microscopy implies that this bilayer architecture may work for other iron pnictide systems and pave the way for the fabrication of superconducting/ferromagnetic heterostructures.