Dresden 2006 – scientific programme
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MA: Magnetismus
MA 20: Poster: Films(1-36) Transp(37-56) Ex.Bias(57-67) Spindyn(68-80) Micromag(81-95) Particle(96-109) Imag.+Surface(110-113) Spinelectr(114-122) Theory+Micromag(123-131) Spinstr+Aniso(132-142) MagMat(143-156) Meas(157,158) MolMag+Kondo(159-162) Postdead(163-)
MA 20.152: Poster
Tuesday, March 28, 2006, 15:15–19:15, P1
Diluted magnetic semi-conductors based on Half-Heusler compounds: CoTi1−xYxSb (Y=Fe,Mn) — •Kristian Kroth1, Benjamin Balke1, Fred Casper1, Andrei Gloskowski1, Vadim Ksenofontov1, Der-Hsin Wei2, Hong-Ji Lin2, Gerhard H. Fecher1, and Claudia Felser1 — 1Johannes Gutenberg - Universität, 55099 Mainz, Germany — 2NSRRC, Hsinchu, 30076, Taiwan
CoTiSb is shown to be a semiconducting half Heusler compound. Doping by Mn or Fe is found to result in ferromagnetic order with metallic like conductivity. Polycristalline samples were produced by arc-melting and their chemical composition was checked by means of photoemission spectroscopy (ESCA) and microscopy (PEEM).
It was found that Ti can be replaced by up to 10% Fe while its crystal structure still remains C1b, which was proved by X-ray powder diffraction and Mößbauer spectroscopy. The strucure stayed stable upon Mn doping up to 40%.
SQUID magnetometry revealed for CoTi0.95Fe0.05Sb a magnetic moment of 0.2µB per unit cell and a Curie temperature of above 700K. SCF calculations using the KKR-CPA method predict a half-metallic ferromagnetic character with only Fe atoms contributing to the total magnetization of the alloy, in agreement to experiments using XMCD at L2,3 edges to determine the atomic resolved contribution of the 3d metals to the magnetic moment. Curie temperatures of about 470K were found upon partially replacement of Ti bei Mn.