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MA: Fachverband Magnetismus

MA 28: Magnetic Thin Films III

MA 28.5: Talk

Thursday, February 28, 2008, 15:30–15:45, H 1012

Investigation of ferromagnetism in oxygen deficient Hafnium oxide thin films — •Erwin Hildebrandt¹, Jose Kurian¹, Yoshiharu Krockenberger¹, Andreas Suter², Fabrice Wilhelm³, Andrei Rogalev³, and Lambert Alff¹ — ¹Institut für Materialwissenschaft, TU Darmstadt — ²PSI, Villingen, Schweiz — ³ESRF, Grenoble, Frankreich

Oxygen deficient thin films of hafnium oxide were grown on single crystal r-cut and c-cut sapphire by reactive molecular beam epitaxy. RF-activated oxygen was used for the in situ oxidation of hafnium oxide thin films. Oxidation conditions were varied substantially in order to create oxygen deficiency in hafnium oxide films intentionally. The films were characterized by x-ray and magnetic measurements. X-ray diffraction studies show an increase in lattice parameter with increasing oxygen deficiency. Oxygen deficient hafnium oxide thin films also showed a decreasing bandgap with increase in oxygen deficiency. The magnetisation studies carried out with SQUID did not show any sign of ferromagnetism in the whole oxygen deficiency range. X-ray magnetic circular dichroism measurements also confirmed the absence of ferromagnetism in oxygen deficient hafnium oxide thin films.