Dresden 2003 – scientific programme

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MA: Magnetismus

MA 2: Magnetische Dünne Schichten I

MA 2.8: Talk

Monday, March 24, 2003, 12:00–12:15, HSZ/04

Short-range magnetic correlation and dimensional crossover in the long-period antiferromagnet Ho — •Holger Ott¹, E. Schierle¹, C. Schüßler-Langeheine^1,2, G. Kaindl¹, E. Weschke¹, V. Leiner^3,4, and H. Zabel³ — ¹Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany — ²II. Physikalisches Institut, Universiät zu Köln, Zülpicher Str. 77, D-50937 Köln, Germany — ³Institut für Experimentalphysik/Festkörperphysik, Ruhr-Universität Bochum, D-44780 Bochum, Germany — ⁴LSS, Institut Laue Langevin, F-38042 Grenoble Cédex, Fance

The helical antiferromagnetic structure of Ho metal was studied in ultra-thin films of thicknesses down to 11 atomic layers by means of resonant magnetic soft x-ray diffraction. For the thinnest film, short-range magnetic correlations were found in a large temperature interval above the Néel temperature. This behavior is attributed to a 3D → 2D transition occuring in a thickness-range between 16 and 11 atomic layers. We show that the anomalous thermal expansion of Ho metal due to the magneto-elastic coupling is related to this short-range magnetic environment rather than to long-range magnetic order.