The ferromagnetic to nonferromagnetic (alpha-beta) phase transition in epitaxial MnAs layers on GaAs(100) is studied by x-ray magnetic circular dichroism and x-ray magnetic linear dichroism photoemission electron microscopy in order to elucidate the nature of the controversial nonferromagnetic state of beta-MnAs. In the coexistence region of the two phases the 6 phase shows a clear XMLD signal characteristic of antiferromagnetism. The nature and the possible causes of the elusiveness of this magnetic state are discussed. (C) 2007 American Vacuum Society