Synthesis of MnSi1.7 nanosheet bundles from CaSi2 crystal powders using MnCl2 in molten salt.

MnSi_1.7 nanosheet bundles with an improved homogeneous composition were synthesized by annealing from CaSi₂ crystal powders with MnCl₂ in molten salt. The MnSi and Si phases were formed at the initial stage of the synthesis with an inhomogeneous Mn distribution within the nanosheet bundles. Subsequently, the phases were transformed into MnSi_1.7 with an improved homogeneous Mn distribution within them for 10 h annealing in the molten salt. The formation of multiple Mn-silicide phases and remarkable improvement in the structural homogeneity of the MnSi_1.7 nanosheet bundles were discussed in terms of the reactions of Mn or Si with chloride compounds, decomposition of chlorides at elevated temperatures, phase selection of multiple silicide phases, shrinkage of the volume from Si to MnSi_1.7, and dominant diffusion species. Multiple growth variants of the MnSi_1.7 domains were stacked in the nanosheets. For comparison, the growth in a deliquescent environment realized by NH₄Cl addition was examined. [ABSTRACT FROM AUTHOR]