Thermal avalanches near a Mott transition

We probe the volume collapse transition (Delta V=V-o similar to 15%) between the isostructural gamma and alpha phases (T similar to 100 K) of Ce0.9Th0.1 using the Hall effect, three-terminal capacitive dilatometry, and electrical resistivity measurements. Hall effect measurements confirm the itinerant ground state as the carrier concentration increases by a factor of 7 in the alpha phase, gamma phase (n(H) = 5.28 x 10(26) m(-3)), and the alpha phase (n(H) = 3.76 x 10(27) m(-3)). We were able to detect a noise spectrum consisting of avalanches while slowly varying the temperature through the hysteretic region. We surmise that the avalanches originate from intergranular stresses at the interfaces between partially transformed high-volume and low-volume phases. The statistical distribution of avalanches obey power laws with energy exponent epsilon similar or equal to 1.5. Hall effect measurements, combined with universal critical exponents, point to short electron mean-free percolation pathways and carrier localization at phase interfaces. Carrier localization was predicted many years ago for elemental cerium by Johansson (1974 Phil. Mag. 30 469).