Magnetic properties of CeB6, PrB6, EuB6, and GdB6

Abstract

The results of a study of the magnetic properties of the hexaborides of cerium, praseodymium, europium, and gadolinium at temperatures from 7 to 300 °K are reported. The susceptibility of CeB6 obeys a Curie-Weiss law, χ = C/(T – θ), above 200 °K with a moment of 2.51 μβ and θ = −82 °K. PrB6 obeys a Curie-Weiss law above 100 °K with a moment of 3.64 μβ and θ = −41 °K. The reciprocal susceptibility of PrB6 shows a minimum at 8.3 °K associated with an antiferromagnetic transition. Europium hexaboride is ferromagnetic at low temperatures with a Curie point of 8.8 °K. The initial reciprocal susceptibility in the range from 9 to 14 °K varies at (T – TC)1,20. Above 30 °K the susceptibility of EuB6 accurately obeys a Curie-Weiss law with θ = −0.5 °K and μeff = 7.90 μβ. Magnetization curves and isotherms of σ2 vs. H/σ are given for EuB6 for temperatures just above the Curie point. The susceptibility of GdB6 obeys a Curie-Weiss law above 70 °K with θ = −66.5 °K and μeff = 7.98 μβ. Further, an antiferromagnetic transition exists at (16.4 ± 0.2) °K. Finally, X-ray diffraction data were obtained for the four compounds yielding lattice constants of 4.140 Å, 4.131 Å, 4.175 Å, and 4.109 Å for CeB6, PrB6, EuB6, and GdB6 respectively.