Magnetic Properties of Filled Skutterudite Phosphides with Heavy Lanthanides Synthesized under High Pressure

Filled skutterudite phosphides with heavy lanthanides Ln T 4 P 12 ( Ln = Gd, Tb, Dy, T = Fe, Ru, Os) were prepared at high temperatures and high pressures. The magnetic properties of these compounds were studied in detail through electrical resistivity ρ( T ), magnetic susceptibility, magnetization, specific heat, and thermoelectric power S ( T ) measurements. The filled skutterudite DyRu 4 P 12 was synthesized for the first time. DyRu 4 P 12 shows an antiferromagnetic transition at T N = 15 K. The dramatic increase at T N observed in ρ( T ) and S ( T ) suggest the formation of a superzone gap due to Fermi surface nesting. All the compounds undergo a ferromagnetic or antiferromagnetic transition at low temperatures except TbOs 4 P 12 . TbOs 4 P 12 is found to be paramagnetic down to 2 K. The magnetic ordered states of filled skutterudite phosphides containing heavy lanthanides are discussed.