Dresden 2003 – wissenschaftliches Programm
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DY: Dynamik und Statistische Physik
DY 37: Critical phenomena and phase transitions II
DY 37.5: Vortrag
Mittwoch, 26. März 2003, 17:30–17:45, G\"OR/229
Critical Phenomena near the Surface of Antiferromagnetic Single Crystals and Thin Films studied by Depth Selective CEMS — •Sarbari Bhattacharya1, B. Stahl1,2, M. Ghafari1, and H. Hahn1 — 1Fachbereich Material- und Geowissenschaften, Petersenstr. 23, TU Darmstadt, 64287 Darmstadt — 2Institiut für Nanotechnologie, Forschungszentrum Karlsruhe, 76021 Karlsruhe
We have already reported the observation of a wetting phenomena near the Néel temperature in single crystalline FeBO3. DCEMS experiments carried out on two γ-FeOOH thin films of different thicknesses reveal a similar magnetic behaviour. Two main components can be seen in the Mössbauer Spectrum measured at 10K for the thicker film . One component is clearly bulk like. The average hyperfine field of this component varies in a manner analogous to that of bulk γ-FeOOH with rise in temperature indicating that it has the same Néel temperature. The magnetization dynamics with increasing temperature of the other component, on the other hand, is clearly very different. It shows marked similarities with the behaviour of the wetting layer in single crystalline FeBO3.