  Single crystalline Mn2-xFexBO4 with x = 0.3, 0.5, 0.7 grown by the flux
method have been studied by means of X-ray diffraction and X-ray absorption
spectroscopy at both Mn and Fe K edges. The compounds were found to crystallize
in an orthorhombic warwickite structure (sp. gr. Pnam). The magnetization data
have revealed a spin-glass transition at TSG= 11, 14 and 18 K for x= 0.3, 0.5
and 0.7, respectively.
