Formation of the α''-phase and study of the solubility of Mn in Cd3As2

• Published in: Journal of alloys and compounds 2022-02, Vol.892, p.162082, Article 162082
• Main Authors: Ril’, A.I., Marenkin, S.F., Volkov, V.V., Oveshnikov, L.N., Kozlov, V.V.
• Format: Article
• Language: English
• Subjects: Cd3As2 system; Crystal structure; Magnetic measurement; Manganese; Mn-doped Cd3As2; Phase diagram Cd-As; Phase transitions; Solubility; Structural modifications of Cd3As2; X-ray diffraction and thermal analysis of Cd3As2
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2021.162082

•Mn-doped Cd3As2 crystals were obtained from elemental and binary precursors.•Mn doping promotes structural transition into secondary polymorph modification.•At lower Mn content ternary Cd3−xMnxAs2 compound is formed.•Above solubility limit (x~0.13) the MnAs phase was detected.•The formation of CdAs2 phase in Cd3−xMnxAs2 + MnAs composites is suppressed. [Display omitted] We studied the effect of Mn on the structure and properties of Cd3−xMnxAs2 crystals with x = 0–0.24, synthesized by direct fusion of high-purity elements. Obtained X-ray diffraction patters suggest that the incorporation of Mn promotes a structural phase transition from primary α-Cd3As2 (x = 0) phase to the α''– Cd3As2 (x = 0.24) phase, while at intermediate compositions both phases can coexist. In addition, the increase of Mn content results in the decrease of lattice cell parameters, which effectively saturates for x > 0.13. Microstructural, calorimetric and magnetometry studies suggest that at high Mn content (x = 0.24) secondary MnAs phase appears. Using obtained results, we estimated the solubility limit of Mn in Cd3As2 as x~0.13, which corresponds to the formation of ternary Cd3−xMnxAs2 compound where Cd atoms are partially substituted by Mn. Formation of ternary compound was also suggested by the results for Cd3As2 + MnAs composite systems, where we also observed the presence of CdAs2 phase, which is a byproduct of corresponding reaction. Additional studies suggested that the CdAs2 phase formation in composite system can be prevented if one uses the Cd3−xMnxAs2 compound instead of pure Cd3As2 as a matrix material.