Resistivity of liquid Rb-Pb and Cs-Pb alloys

Measurements of the resistivity rho of liquid Rb-Pb and Cs-Pb alloys as a function of composition and temperature are presented. Around the equiatomic composition, the resistivity reaches non-metallic values in both systems; equiatomic Cs-Pb ( rho =7000 mu Omega cm at T=620 degrees C) may be classified as a liquid semiconductor. This is explained in terms of the liquid structure of these alloys, in which the Pb ions presumably join in covalently bound clusters. With rising temperatures, these clusters disintegrate. As a consequence, the resistivity decreases rapidly. For the Cs-Pb system, a DSC (differential scanning calorimetry) survey of the liquidus temperature as a function of composition has been performed. A tentative Cs-Pb phase diagram is presente