Tetragonal distortion of Mn films on Cu3Au(100)

The magnetism, structure, and growth of thin Mn films on Cu3Au(100) have be en investigated by low-energy electron diffraction (LEED) including I/V mea surements, Auger electron spectroscopy, medium-energy electron diffraction, and the magneto-optical Kerr effect. Up to 20 ML Mn could be grown layer b y layer. The films adopt the in-plane spacing of the Cu3Au(100) substrate. The LEED I(V) analysis finds two different structural phases. Their atomic volume differs by 7%. In addition, both structures have different tetragona l distortions. The interior of thick Mn films is characterized by a conside rable tetragonality of a cubic phase. Such a distortion is also found for M n on Ag(100) [P. Schieffer, C. Krembel, hi. C. Hanf, D. Bolmont, and G. Gew inner, J. Magn. Magn. Mater. 165, 180 (1997)], even though the atomic volum e of these films is larger by 10%. Both structures can be attributed to ela stic deformations of a single phase. The absence of any measurable Kerr ell ipticity as well as the tetragonal distortion of this structure can be expl ained by a particular arrangement of magnetic moments in an antiferromagnet ic phase. [S0163-1829(99)02832-5].