Berlin 2015 – scientific programme

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MA: Fachverband Magnetismus

MA 19: POSTER Ia

MA 19.61: Poster

Tuesday, March 17, 2015, 09:30–13:00, Poster A

Structural and magnetic characterization of α^′−Fe₈N_x thin films — •Tim Helbig, Imants Dirba, Oliver Gutfleisch, and Lambert Alff — Material Science, TU Darmstadt, Alarich-Weiss-Str. 16, 64287 Darmstadt, Germany

Buffer-free and epitaxial α−Fe and α^′−Fe₈N_x thin films have been grown by RF magnetron sputtering onto MgO (100) substrates. With increasing nitrogen content in the plasma during deposition, an expansion of the α−Fe unit cell along the c−axis was observed resulting in a tetragonal distortion of approximately 10% (c = 3.15 Å) which corresponds to the value for α^′−Fe₈N (002). Fe bcc lattice expansion led to an increase in magnetic moment up to 2.61 ± 0.06 µ_B per Fe atom and an increased anisotropy of around 6000 Oe compared to that of pure Fe film (at 10 K temperature). Magnetic Force Microscopy (MFM) measurements have been performed indicating a transition from in plane magnetization due to shape anisotropy, to out of plane magnetization caused by the strain-induced magnetocrystalline anisotropy along the c−axis.