Tetragonal distortion of Mn films onCu3Au(100)

Abstract

The magnetism, structure, and growth of thin Mn films on ${\mathrm{Cu}}_{3}\mathrm{Au}(100)$ have been investigated by low-energy electron diffraction (LEED) including $I/V$ measurements, Auger electron spectroscopy, medium-energy electron diffraction, and the magneto-optical Kerr effect. Up to 20 ML Mn could be grown layer by layer. The films adopt the in-plane spacing of the ${\mathrm{Cu}}_{3}\mathrm{Au}(100)$ substrate. The LEED $I(V)$ analysis finds two different structural phases. Their atomic volume differs by 7%. In addition, both structures have different tetragonal distortions. The interior of thick Mn films is characterized by a considerable tetragonality of a cubic phase. Such a distortion is also found for Mn on Ag(100) [P. Schieffer, C. Krembel, M. C. Hanf, D. Bolmont, and G. Gewinner, J. Magn. Magn. Mater. 165, 180 (1997)], even though the atomic volume of these films is larger by 10%. Both structures can be attributed to elastic deformations of a single phase. The absence of any measurable Kerr ellipticity as well as the tetragonal distortion of this structure can be explained by a particular arrangement of magnetic moments in an antiferromagnetic phase.