Thermal response of the iron-based Ba122 superconductor to in situ and ex situ processes

TL;DR

This study investigates the thermal properties of the Ba122 superconductor, revealing its melting point to be approximately 1300°C through calorimetry and microstructural analysis, which is crucial for optimizing fabrication processes.

Contribution

The paper provides the first detailed calorimetric analysis of Ba122's thermal response during in situ and ex situ synthesis routes, clarifying its melting behavior.

Findings

Melting point of Ba122 is approximately 1300°C.

Thermal responses differ between in situ and ex situ processes.

Microstructural analysis supports calorimetric data.

Abstract

The thermal properties are one of the key parameters to control phase purity and microstructure of polycrystalline materials. The melting point of the iron-based BaFe2As2 superconductor (Ba122), which foresees high-field applications, remains controversial. In this work, thermogravimetry-differential scanning calorimetry measurements (TG-DSC) of undoped and Co-doped Ba122 were carried out. Mixtures of elemental metals and pre-reacted Ba122 powders were prepared to investigate the thermal responses during in situ and ex situ synthesis routes, respectively. In addition, the phases and microstructures of the quenched samples were evaluated to elucidate the observed exothermic/endothermic peaks. Our results suggest that the melting point of Ba122 is ~1300{\deg}C.