SYNTHESIS AND CHARACTERIZATION OF NEW INTERMETALLIC COMPOUNDS M-3(ASTE3)(2) (M=CR, FE, CO)

The new amorphous intermetallic compounds, M-3(AsTe3)(2):M=Cr, Co, Fe, were synthesized by the precipitation reaction of the Zintl anion AsT e33- with the divalent transition metal halides in aqueous solution an d analyzed by EDS equipped with SEM and PIXE. The empirical formula of the specimens was found to be Fe30As1.8Te5.9, CO(3.0)AS(2.1)Te(6.5), and Cr3.0As2.0Te6.9 by the quantitative elemental analysis. The de spe cific resistivity of the materials was measured as a function of tempe rature in the range from 20 to 300 K, in which their resistivities wer e decreased with increasing temperature, indicating the specimens to b e semiconductors. The resistivity of Cr-3(AsTe3)(2) was largely depend ent on temperature, while those of Co-3(AsTe3)(2) and Fe-3(AsTe3)(2) w ere only slightly dependent on temperature. To characterize the spin g lass state of the specimens, the ac and de magnetic susceptibility wer e measured and it was found that Co-3(AsTe3)(2) and Fe-3(AsTe3)(2) und ergo a transition to a spin glass state at 6 K and 38 K, respectively. Magnetization data are reported as both thermal remanent magnetizatio n (TRM) and isothermal remanent magnetization (IRM) as a function of m agnetizing field and temperature.