Substitutional effect on the transport properties of MnSi

We report the transport properties, including electrical resistivity (r) and Seebeck coefficient (S) of Ge-substituted MnSi1 xGex (with x 1⁄4 0, 0.02, 0.05, and 0.10) alloys as a function of temperature between 10 and 300K. It was found that the partial substitution of Ge at Si site has a surprisingly weak effect on the ferromagnetic transition temperature TC in MnSi, indicating that the negative chemical pressure produced by the substitution of larger ion Ge in place of Si is unable to significantly influence the magnetic ordering. In addition, the temperature-dependent Seebeck coefficient shows similar behaviour for theses alloys, which suggests that the electronic density of states (DOS) of MnSi near the Fermi level is essentially unaffected by Ge substitution for Si. r 2006 Elsevier B.V. All rights reserved. PACS: 71.20.Be; 72.15.Jf; 75.50.Cc