The first ternary intermetallic heusler nanoparticles: Co/sub 2/ FeGa (abstract)

Synthesis of materials with controlled particle size in nanometer regime is an active area in the field of materials research. With the control over particle size the electronic and magnetic properties of material can be tuned. To study the effect of nanometer dimensions on the properties of Heusler alloys, a first example of Nano-Heusler is presented. Co/sub 2/FeGa Heusler nanoparticles were produced by reducing methanol impregnated mixture of CoCl/sub 2/.6H/sub 2/O, Fe (NO/sub 3/)3.9H/sub 2/O and Ga(NO/sub 3/)3. X H/sub 2/O after loading on fumed silica. The dried samples were heated under pure H/sub 2/gas at 900 deg. C. The synthesized Co/sub 2/FeGa Heusler nanoparticles were characterized by HRTEM, XRD and Moessbauer spectroscopy. All peaks of XRD patterns can be attributed to a L2/sub 1/ Heusler structure with the lattice constant a/sub o/= 0.537 deg. A. The size of the particles, as determined by transmission electron microscopy, is between 16-20 nm. Ferromagnetic behavior of the particles as determined by the SQUID is presented and compared with the bulk Co/sub 2/FeGa Heusler alloy. (author)