Berlin 2012 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 72: [MA] Joint Session "Surface Magnetism III" (jointly with O)
O 72.7: Vortrag
Donnerstag, 29. März 2012, 16:45–17:00, BH 243
Enhanced magnetoelastic coupling of Fe layers on the NiO/Ag(001) — •Anita Dhaka, Dirk Sander, and Jürgen Kirschner — Max-Planck-Institut für Mikrostrukturphysik, 06120 Halle, Germany
Magnetoelastic (ME) coupling is the driving force for magnetostriction of bulk samples. The ME coupling coefficients B1 and B2 determine the magnetostriction λ100 and λ111, respectively, of cubic systems. They also determine the impact of lattice strain on the magnetic anisotropy. Therefore their experimental determination is of utmost importance for the understanding of magnetic anisotropy of epitaxially strained monolayers [1]. We have performed in-situ ME stress measurements on Fe monolayers on epitaxially grown NiO/Ag(001) to investigate the effect of an antiferromagnetic (AFM) buffer layer on the magnetoelasticity of ferromagnetic (FM) monolayers. Here, we measured the ME coupling coefficient B2 of 6 monolayer (ML) Fe, which is unexpectedly large. We find B2=−19.6± 1.6 MJ/m3, which differs in both magnitude and sign from the bulk value of +7.83 MJ/m3 [1]. For the deposition of 6 ML Fe on Ag(001) we measure B2=+2± 0.6 MJ/m3, which is almost a factor of four smaller than the bulk value. Notably, the induced strain in the Fe film on both substrates is comparable. This suggests that the FM-AFM interface plays an important role for the enhanced B2 of Fe on NiO.
[1] D. Sander, Rep. Prog. Phys. 62, 809 (1999).