Influence of growth flux solvent on anneal-tuning of ground states in CaFe2As2

TL;DR

This study examines how different growth flux solvents influence the anneal-tuning of structural and magnetic phases in CaFe2As2, revealing similar tunability but differing sensitivities to annealing conditions.

Contribution

It compares the effects of Sn flux and self-flux synthesis methods on phase tunability and sensitivity to annealing in CaFe2As2, expanding understanding of growth condition impacts.

Findings

Both flux methods allow phase tuning via annealing.

Sn flux samples show less sensitivity to annealing temperature.

Phase diagram shifts with different growth fluxes.

Abstract

The effects of anneal-tuning of single-crystalline samples of CaFe$_2$As$_2$ synthesized via a molten Sn flux method are investigated using x-ray diffraction, chemical composition, electrical transport and magnetic susceptibility measurements in order to understand the role of growth conditions on the resultant phase diagram. Previous studies of CaFe$_2$As$_2$ crystals synthesized using a self-flux (FeAs) method revealed an ability to tune the structural and magnetic properties of this system by control of post-synthesis annealing conditions, resulting in an ambient pressure phase diagram that spans from tetragonal/orthorhombic antiferromagnetism to the collapsed tetragonal phase of this system. In this work, we compare previous results to those obtained on crystals synthesized via Sn flux, finding similar tunability in both self- and Sn-flux cases, but less sensitivity to annealing temperatures in the latter case, resulting in a temperature-shifted phase diagram.