High pressure electrical resistance behaviour of dialuminides of thorium and uranium

In this paper we report the pressure-induced electrical resistance behaviour of the dialuminides of thorium and uranium up to 8 and 11 GPa, respectively. ThAl₂ shows a rapid decrease in resistance up to 2.5 GPa and thereafter it decreases slowly. The electrical resistance of UAl₂ also decreases monotonically and it shows a collapse in resistance above a pressure of 9 GPa where our own previous high-pressure X-ray diffraction results indicated the occurrence of a structural phase transition from cubic (MgCu₂) to hexagonal (MgNi₂) phase. The marked difference in the pressure-induced electrical resistance behaviour of these two systems is discussed by taking into account the contributions from interband scattering and spin-fluctuation scattering mechanisms in ThAl₂ and UAl₂, respectively.