Effect of Si substitution on anti-invar behavior of Y6(Mn1−xSix)23 compounds

The anti-invar effect in Y 6 (Mn 1-x Si x ) 23 compound system has been investigated and the results are compared with those in Y 6 (Mn 1-x M x ) 23 compounds (M=Al, Fe). From the relation between the Curie temperature T C and the thermal expansion coefficient α, α is larger in M = Si than in M = Fe and Al for the compounds of the same T C . The present results strongly imply that the Si substitution results in the reduction of the exchange interaction without a strong change in the intra-atomic Coulomb interaction.