Regensburg 2013 – scientific programme
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MA: Fachverband Magnetismus
MA 26: Magnetic Thin Films I of 2
MA 26.4: Talk
Wednesday, March 13, 2013, 10:15–10:30, H3
La2CrWO6: A Possible Antiferromagnet Half-Metal — •Mehran Vafaee, Mehrdad Baghaie Yazdi, Vikas Shabadi, Philipp Komissinskiy, and Lambert Alff — Institute of Materials Science, Technische Universität Darmstadt, Petersenstr. 23, 64287 Darmstadt, Germany
Half-metallic antiferromagnets, materials with zero net magnetization and 100% spin polarization of charge carriers, are promising for spintronic applications, but have never been synthesized up to now. La2CrWO6 with d3-d3 configuration has been suggested as a strong candidate based on density functional theory [1]. However, due to the unusual valence state of W3+, this material is thermodynamically unstable. For the first time, we report the thin film synthesis of La2CrWO6 by pulsed laser deposition. X-ray absorption spectroscopy at the Cr K-edge and W L2,3-edges show +3 valence state for Cr and a mixed valence state of +3 / +5 for W. X-ray linear dichroism confirms undistorted Cr octahedra symmetry. The magnetization shows ferrimagnetic instead of antiferromagnetic behavior. X-ray magnetic dichroism measurements indicate that antisite disorder is responsible for the reduced W magnetic moment. Thus, suppression of antisite disorder is an important strategy to obtain half-metallic antiferromagnets in double perovskites.
[1] V. Pardo and W. E. Pickett, Phys. Rev. B 80, 054415 (2009).