Correlating synthesis, structure and thermal stability of CuBi nanowires for spintronic applications by electron microscopy and in situ scattering methods

TL;DR

This study investigates how synthesis conditions affect the structure and thermal stability of Bi-doped copper nanowires, aiming to optimize their spintronic properties through detailed electron microscopy and scattering analyses.

Contribution

It provides new insights into the relationship between synthesis parameters, microstructure, and thermal stability of CuBi nanowires for spintronic applications.

Findings

Larger crystalline domains enable homogeneous Bi incorporation.

Smaller domains lead to Bi accumulation at grain boundaries.

Bi diffuses out upon heating, forming rhombohedral Bi upon cooling.

Abstract

Bi-doped copper (Cu1-xBix) nanowires (NWs), promising candidates for spintronic applications due to their potential for a giant spin Hall effect (SHE), were synthesized and their structural properties and thermal stability were investigated. Using template-assisted electrodeposition, Cu1-xBix nanowires with varying bismuth (Bi) content (x=0, 2, 4, and 7%) and different crystalline domain sizes were fabricated. Structural analysis by advanced electron microscopy and X-ray scattering techniques revealed the influence of synthesis conditions on the resulting NW crystal structure and microstructure, including Bi localization (within the lattice or in the grain boundaries), crystallite domain dimensions, and lattice distortions. While NWs with larger crystalline domains allow homogeneous Bi incorporation into the Cu lattice, NWs with smaller crystalline domains exhibit noticeable Bi accumulation at grain boundaries. The thermal stability of the NWs was examined using variable temperature X-ray diffraction and total scattering. Upon heating, lattice distortions consistent with Bi diffusion out of the Cu lattice were observed, with subsequent crystallization of rhombohedral metallic Bi upon cooling. These findings establish a foundation for optimizing the SHE performance of Cu1-xBix nanowires for spintronic devices by correlating synthesis parameters with microstructural features and thermal behavior.