muSR and inelastic neutron scattering investigations of the caged type Kondo semimetals: CeT2Al10 (T=Fe, Ru and Os)

Recently the Ce-based caged-type compounds having general formula CeT2Al10 (T=Fe, Ru and Os) have generated considerable interest due to the Kondo semiconducting paramagnetic ground state (down to 40 mK) observed in CeFe2Al10 and anomalously high magnetic ordering temperature with a spin gap formation at low temperatures in Kondo semimetals CeRu2Al10 and CeOs2Al10. The formation of long-range magnetic ordering out of the Kondo semiconducting/semimetallic state itself is extraordinary and these are the first examples of this enigmatic coexistence of electronic ground states. These compounds also exhibit strong anisotropy in the magnetic and transport properties, which has been explained on the basis of single ion crystal electric field (CEF) anisotropy in the presence of strongly anisotropic hybridization between localised 4f-electron and conduction electrons. Further they also exhibit a remarkable modification of magnetic and transport properties with doping on Ce, or T or Al sites. In this review we briefly discuss the bulk properties of these compounds, giving a detailed discussion on our muon-spin-relaxation (muSR) investigations and inelastic neutron scattering (INS) results.
Comment: 36 pages, 21 figures, 2 tables. Physica Scripta (2013)