Inhomogeneous level splitting in Pr2-xBixRu2O7

We report that Bi doping drives Pr2-xBixRu2O7 from an antiferromagnetic insulator (x=0) to a metallic paramagnet (x≈1) with a broad low T maximum in C/T. Neutron scattering reveals local low energy spin excitations (ℎω≈1 meV) with a spectrum that is unaffected by heating to kBT>>ℎω. We show that a continuous distribution of splittings of the non-Kramers Pr3+ ground-state doublet such as might result from various types of lattice strain can account for all the data.
paramagnetic materials, praseodymium compounds, neutron diffraction, metal-insulator transition, antiferromagnetic insulato, Bi doping, metallic paramagnet, bismuth compounds, antiferromagnetic materials, neutron scattering, local low energy spin excitations, nonKramers ground-state doublet, lattice strain, Pr2-xBixRu2O7
Physical Review Letters, vol. 94, Issue 17, id. 177201