Kondo-type behavior in Fe 2 − x M x TiSn ( M = Co , Ni )

Magnetization and electrical resistivity measurements have been made on ${\mathrm{Fe}}_{2\ensuremath{-}x}{\mathrm{Ni}}_{x}\mathrm{TiSn}$ and ${\mathrm{Fe}}_{2\ensuremath{-}x}{\mathrm{Co}}_{x}\mathrm{TiSn}$ cubic solid solutions. The electrical resistivity reveals a strong influence of spin fluctuations for ${\mathrm{Fe}}_{2\ensuremath{-}x}{\mathrm{Co}}_{x}\mathrm{TiSn},$ while it exhibits Kondo-like behavior for ${\mathrm{Fe}}_{2\ensuremath{-}x}{\mathrm{Ni}}_{x}\mathrm{TiSn}.$ The magnetic susceptibility of ${\mathrm{Fe}}_{2}\mathrm{TiSn}$ and its alloys with Ni and Co indicates the occurrence of weak ferromagnetism, which may be induced by atomic disorder. Comparison of the resistivity and susceptibility of both series of alloys indicates that ${\mathrm{Fe}}_{2}\mathrm{TiSn}$ is a Kondo-lattice system with a small pseudogap located at the Fermi level. The pseudogap is strongly reduced by local disordering.