Synthesis and single crystal study of CuMn₃As₂ and Cu₂Mn₄As₃

We report on single-crystal growth, and crystal structure of CuMn₃As₂ and Cu₂Mn₄As₃ compounds. Magnetic properties of Cu₂Mn₄As₃ were studied in temperature range between 2 and 400 K. The single crystals were prepared from bismuth flux and characterized by means of single crystals diffraction, electron-microprobe analysis, magnetic and resistivity measurements. Crystal structures of CuMn₃As₂ and Cu₂Mn₄As₃ were determined by synchrotron radiation x-ray diffraction experiments at 100 K. The CuMn₃As₂ and Cu₂Mn₄As₃ crystallize in an orthorhombic structure with very similar lattice parameters. Magnetic and resistivity measurements on Cu₂Mn₄As₃ suggest existence of long range magnetic order below 315 K with another magnetic transition at 45 K. - Highlights: • Cu_1+xMn_1−xAs single crystals can be grown using bismuth flux. • Crystal structure of CuMn₃As₂ and Cu₂Mn₄As₃ refined from single crystal x-ray diffraction data. • The orthorhombic unit cell of CuMn₃As₂ and Cu₂Mn₄As₃ twice as large compared to CuMnAs. • Cu₂Mn₄As₃ is a new compound with magnetic order below 300 K and semi-metallic behavior.