Phase equilibria in the MnSb4Te7-MnBi4Te7 system and characterization of tetradymite-type layered solid solutions

Phase equilibria and structural evolution in the MnSb 4 Te 7 -MnBi 4 Te 7 system were systematically investigated to understand the formation and stability of tetradymite-type layered solid solutions via Xray diffraction (XRD), differential thermal analysis (DTA), and scanning electron microscopy (SEM) and its T-x diagram was plotted.XRD analysis confirmed that all synthesized MnSb 4-x Bi x Te 7 (0 x 4) alloys crystallize in a single-phase trigonal structure (P-3m1), with no evidence of secondary phases.The gradual substitution of Sb 3+ by the larger Bi 3+ ions resulted in a monotonic increase in lattice parameters which determined via Le Bail method, indicating the formation of a continuous solid solution.SEM imaging further confirmed the homogeneous microstructure of the samples, with no visible phase separation or compositional inhomogeneity.The T-x diagram of system is characterized by peritectic transformations.Due to MnSb 4 Te 7 and MnBi 4 Te 7 melt incongruently, pseudobinary behavior was observed only in the subsolidus region.The findings highlight the potential of these solid solutions for desired properties, essential for applications in magnetic topological insulators and quantum materials.