Regensburg 2010 – scientific programme
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MA: Fachverband Magnetismus
MA 27: Spin Structures and Magnetic Phase Transitions
MA 27.3: Talk
Thursday, March 25, 2010, 17:45–18:00, H10
Weak random anisotropy in the two-dimensional limit - FeZr-based thin films and multilayers — •Andreas Liebig1, Panagiotis Korelis2, Gabriella Andersson2, Manfred Albrecht1, and Björgvin Hjörvarsson2 — 1Chemnitz University of Technology, Institute of Physics, Chemnitz, Germany — 2Dept. of Physics and Material Sciences, Uppsala University, Uppsala, Sweden
We present a study on the magnetic properties of Fe90Zr 10/Al70Zr30 amorphous multilayers, based on MOKE and SQUID magnetometry. Fe90Zr10 is an archetypical example for a reentrant ferromagnet, exhibiting spin glass phase at low temperatures and a ferromagnetic phase at intermediate temperatures.
From structural and magnetic measurements we could ensure the absence of a crystalline phase, and interlayer thicknesses of 4.5 nm yielded negligible interlayer exchange coupling. The amorphous layers can therefore be treated as magnetically decoupled, besides dipolar interactions. Consequently, the ordering temperature scales with the thickness of the magnetic layers. Furthermore, the finite thickness influences the character of the phase transition itself. For the low-temperature limit the spin-glass phase is suppressed. Above the apparent ferromagnetic ordering temperature a phase with exceedingly high magnetic susceptibility is found. Similarities with the random anisotropy two-dimensional X-Y model are discussed.