Preliminary study of (Pu1-xAmx) solid solutions

Among the actinides, plutonium is at the critical position between the light actinides with itinerant 5f electrons and the heavy actinides with localized 5f electrons. The change of behavior of the 5f electrons between Pu and Am has been described by Johansson as a Mott-like transition. Although α-plutonium is monoclinic, and α-americium is hexagonal, plutonium alloys with Am exist over a wide range of solubility. This localisation was attributed to a negative chemical pressure due to Am substitution in the Pu-lattice. Therefore the Pu1-xAmx solid solutions appear to be the ideal material to investigate the localisation phenomena of 5f electrons. In the present work, Pu1-xAmx samples with various concentrations of Am were prepared by arc melting pure metals and studied by means of electrical resistivity measurements at low and high temperatures