Berlin 2005 – wissenschaftliches Programm

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MA: Magnetismus

MA 20: Poster:Schichten(1-29),Spintrsp(30-45),Ex-Bias(46-63),Spindyn(64-75),Mikromat.(76-80),Cluster(81-94),Abbv.(95-99),Obflm(100-02),SpElek.(103-09),E-Theo(110-14),Mikromag.(115-16),Spin+PÜ(117-26),Mag.Mat.(127-51),Meth.(152-55),Mol.Mag(156-59),Kondo(160-65

MA 20.141: Poster

Montag, 7. März 2005, 14:00–18:00, Poster TU C

First-principles investigation of electronic structures and vibrational modes of various types of ternary Heusler alloys with L2₁ structure — •Waheed Adeniyi Adeagbo¹, Alexei T. Zayak², and Peter Entel¹ — ¹Institute of Physics, MC 328, University of Duisburg-Essen, Duisburg Campus, Lotharstr.1, 47048, Duisburg, Germany — ²Department of Physics and Astronomy,Rutgers University, 136 Frelinghuysen Rd, Piscataway, NJ 08854-8019, USA

The first-principles method is used to show the trend of instabilities and stabilities exhibited by many Heusler alloys. We have calculated the phonon spectra of various types of ternary Heusler alloys (X₂YZ) with ferromagnetic order (where X and Y are mostly 3d-metals and Z non-magnetic metallic atoms). We correlate the results of the spectra with their corresponding electronic density of states at the Fermi level in order to address some of the trends of anomalous softening behaviour, which is mostly dictated by the TA₂ mode in the acoustic region of the phonon dispersion of some magnetic Heusler alloys. While most series of the non-magnetic Heusler alloys show non-softening in the acoustic mode, the magnetic counterparts are either non-softened or softnened. Our phonon calculations are based on the direct method which yields good agreement with existing experimental data.