The binary system Pu-Si: crystallochemistry and magnetic properties

The crystallochemistry of the plutonium-silicon binary system is being investigated. We report on the observation of five binary phases: PUSi2 (ThSi2 and AlB2 type), PuSi (FeB type), Pu3Si2 (U3Si2 type) and Pu5Si3 (W5Si3 type). Preliminary characterizations of the electronic properties of PUSi2 (ThSi2 type) and PuSi (FeB type) were undertaken by SQUID magnetometry and electrical resistivity measurements. PUSi2 does not order magnetically down to 2 K, whereas PuSi undergoes a ferromagnetic transition at T-C similar to 72 K.