Berlin 2015 – scientific programme
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MA: Fachverband Magnetismus
MA 46: Magnetic Thin Films I
MA 46.4: Talk
Thursday, March 19, 2015, 15:45–16:00, H 1012
Correlation of magnetic moment and lattice expansion in γ′-Fe4N thin films — •Dominik Gölden, Imants Dirba, Erwin Hildebrandt, Philipp Komissinskiy, Oliver Gutfleisch, and Lambert Alff — Institute of Materials Science, Technische Universität Darmstadt, Germany
γ′-Fe4N is the most stable phase among the iron nitrides and can be grown in a wide temperature range. It has been in the focus of research for several decades due to its physical properties such as low electrical resistance, low coercivity, and relatively high saturation magnetization, making it interesting for application in magnetic tunnel junctions. We report on the correlation of the lattice expansion and the magnetic moment of γ′-Fe4N thin films grown by molecular beam epitaxy on single crystal MgO(100) substrates and give an estimate of the Curie temperature. In addition, the electronic properties were studied by X-ray photoelectron spectroscopy to show the influence of the interstitial nitrogen on the electronic structure in the γ-Fe lattice. By changing the nitridation conditions using a nitrogen radical source, the lattice constant of γ′-Fe4N could be varied in a wide range. We have correlated nitridation parameters during thin film growth with the structural and magnetic properties using X-ray diffractometry and SQUID magnetometry.