Dresden 2009 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 13: Poster Ia: Electron Theory (1); Magnetic Imaging (2,3); Thin Films (4-25); MSMA (26-33); Magn. Semiconductors (34-42); Magn. Half Metals and Oxides (43-60)
MA 13.25: Poster
Dienstag, 24. März 2009, 10:15–13:00, P1A
The strained epitaxial Nd-Fe-B films by mechanical elongation — •Ah-Ram Kwon1, Volker Neu1, Vlakimir Matias2, Jens Hänisch1,2, Ruben Hühne1, Bernhard Holzapfel1, Ludwig Schultz1, and Sebastian Fähler1 — 1IFW Dresden, P.O. Box 270116 D-01171 Dresden — 2Los Alamos National Laboratory, Mail Stop T004, Los Alamos NM 8545 USA
Though it is well known that a variation of lattice constants strongly influences the functional properties of materials, most of the experiments are limited to hydrostatic pressure or biaxial stress. Here we present an approach, which impresses a large uniaxial strain on epitaxially grown films in order to tune their functional properties. A ductile Hastelloy substrate covered with a (001) oriented ion beam assisted MgO layer is used. Conventional mechanical elongation after deposition breaks the symmetry within the substrate plane compared to the as-deposited state. Consequences are exemplarily examined for an epitaxial hard magnetic Nd2Fe14B film strained by 2%. Though magnetostriction is usually considered to be negligible in this material exhibiting a high magnetocrystalline anisotropy, the uniaxial strain results in an elliptical distortion of the in-plane anisotropy below the spin-reorientation temperature. Our approach is versatile to study the influence of large strain on various materials, as the used MgO (001) layer is a common substrate for epitaxial growth.