Berlin 2012 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 36: Topical Session Bulk Nanostrucured Materials VIII - Functional Properties I
MM 36.3: Vortrag
Mittwoch, 28. März 2012, 15:45–16:00, H 0106
Magnetooptic Kerr Effect on severely deformed hard and soft magnetic materials — •Peter Jerabek1, Reinhard Pippan2, and Heinz Krenn1 — 1Karl-Franzens-University Graz, Graz, Austria — 2Erich Schmid Institute , Austrian Academy of Sciences, Leoben, Austria
Magnetooptic Kerr effect (MOKE) is sensitive to the vector orientation of magnetization and offers a local probe of the domain structure. The high pressure torsion (HPT) of polycrystalline materials causes severe plastic deformation (SPD) [1] with a grain size refinement and a change of the magnetic domain structure (mostly a magnetic hardening). Ring specimens of different strain status (up to ε = 10) are cut from HPT-deformed disk samples of ferritic steel and silicon-iron (Fe-3% Si). The boundaries between ultrafine grains (<100 nm) impede the motion of magnetic domain walls (accompanied by Barkhausen jumps) and pins the magnetization to preferred (textured) directions. The magnetic hysteresis measured by conventional induction method is compared with the local probe of polar, longitudinal and transverse MOKE (scanning the HeNe-laser spot over different parts of the HPT-ring sample). An interesting aspect is how SPD influences the strain-induced magnetization of originally magnetic soft Fe-3% Si and magnetic hard alloyed steels on the route from the polycrystalline to the dense nanocrystalline structure.
Financial support by the FWF Austrian Science Fund is appreciated (No. S10407-N16).
[1] M. Zehetbauer et al., Adv. Eng. Mat. 12 (2010), 692.