Magnetism, the Kondo Effect and Spin Correlations in TbFe 2 (Si 1-x Ge x ) 2

A series of intermetallic compounds TbFe2(Si1i xGex)2 with 0 · x · 1 and ¢ x = 0:1 was prepared, and x-ray diffraction, electric resistivity and magnetic susceptibility measurements were performed. For all concentrations 0 · x · 1, besides the low temperature Neel point TN and the Kondo temperature TK , the high temperature characteristic points TSC were observed, where spin fluctuations start to influence the transport and magnetic properties of the material. The values of TN and TSC , obtained for different x, have a direct relationship with the behavior of the c-axis, and all these quantities have a minimum at x = 0.4. The decrease of TN with the crystal lattice condensation is rather unusual and can be related to the Kondo mechanism. The TbFe2Ge2 compound can be characterized as an antiferromagnetic Kondo lattice. Some other mechanisms of the TN and TSC behavior are also discussed.