Substitute effects of Ga on AlB2-type superconductor CaAlSi

We present the results of lattice parameters at room temperature and the static magnetic susceptibility between 1.8 and 9.0 K for a series of eleven polycrystalline Ca(Al1-xGax)Si samples with x = 0.0-1.0. Variation of the lattice parameters reveals that there is a movement for c to increase, for a and v to decrease, linearly with increasing x. The superconducting phase diagram of Ca(Al1-xGax)Si shows that there is an explicit minimum T-c close to x = 0.7. This demonstrates that the superconducting transition temperature of the pseudo-binary system Ca(Al1-xGax)Si is not a monotonic function of the lattice constants irrespective of the same valences of Ga and Al. (C) 2004 Elsevier B.V. All rights reserved.