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MA: Fachverband Magnetismus

MA 2: Micro and Nanostructured Magnetic Materials I

MA 2.6: Vortrag

Montag, 25. Februar 2008, 11:30–11:45, EB 301

The first ternary intermetallic Heusler nanoparticles: Co₂FeGa. — •Lubna Basit¹, Aswani Yella¹, Sergej A. Nepijko², Vadim Ksenofontov¹, Gerhard H. Fecher¹, and Claudia Felser¹ — ¹Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg - University, 55099 Mainz — ²Institute of Physics, Johannes Gutenberg - University, 55099 Mainz

Synthesis of materials with controlled particle size on the nanometer scale is an active area in the field of materials research. With the control over particle size, the electronic and magnetic properties of materials can be easily tuned. To study the effect of nanometer dimensions on the properties of Heusler alloys, a first example of Heusler nanoparticles is presented. Co₂FeGa Heusler nanoparticles were produced by reducing a methanol impregnated mixture of CoCl₂.6H₂O, Fe(NO₃)₃.9H₂O, and Ga(NO₃)₃.xH₂O after loading on fumed silica. The dried samples were heated under pure H₂ gas at 900^∘C. The synthesized Co₂FeGa Heusler nanoparticles were characterized by HRTEM, XRD and Mößbauer spectroscopy. All peaks of the XRD pattern can be attributed to a L2₁ Heusler structure with a lattice constant of a=4.37 Å. The size of the particles, as determined by transmission electron microscopy, is between 16 nm and 20 nm. The ferromagnetic behaviour of the particles as determined by the SQUID measurements is presented and compared with the bulk Co₂FeGa Heusler alloy.