[en] A Fermi surface study of the ferromagnetic phase of CeSb is presented. The γ frequency branches arising from the electron surfaces at the X points, three separate frequency branches from the hole surfaces at the GAMMA point and the low frequency branch α have been observed. The effective mass ratios are low and range from approx. 0.2 for the α branch to approx. 1.0 for the high frequency branch of γ. The low effective mass ratios suggest that the admixture of the conduction states with the f state is small. We have observed a drastic change in the appearance of the dHvA signal at the phase transition between the ferromagnetic and lower field antiferromagnetic phases: The low frequency α oscillation suddenly disappears as the crystal enters the antiferromagnetic phase. By utilizing the change in the signal appearance, the transition field strength has been measured as a function of the field direction. The present experimental results, particularly the origin of the α oscillation, are discussed in the light of the p-f mixing theory and recent band structure calculations based on localized f orbitals

[en] The majority of the compounds with Th₃P₄ structure exhibit nonmetallic and/or ferro- or antiferromagnetic properties. Superconductivity in the metallic chalcogenides La₃X₄ (X = S, Se, Te) which contain one excess valence electron per formula unit was discovered recently and fairly high values for the critical temperature T/sub c/were reported. The only nonmagnetic pnictides (thorium pnictides) are valence compounds and at least the phosphide and the arsenide are semiconductors. A large number of rare-earth pnictides of composition Ln₄Pn₃ adopt the anti-Th₃P₄ structure. Again most of these compounds order magnetically. Superconductivity was detected in the La-compounds below 1⁰K Changes of T/sub c/ by substituting part of the cations or the anions are investigated and discussed

[en] Compounds of nominal composition LnIrGa with Ln=La..Nd, Gd..Ho, Tm and some LnRhGa were found to crystallize in the orthorhombic TiNiSi-type structure (ordered Co₂Si type) whereas off-stoichiometric 'ScIrGa' was obtained in the hexagonal MgZn₂-type structure. Ferromagnetic and antiferromagnetic ordering was observed with ordering temperatures of 4 to 66 K. The valence of Ce in CeIrGa is between three and four at room temperature, and close to four in CeRhGa. (orig.)

[en] This paper uses accurate Fermi surface measurements as a test of hybridization models in CeSb. Detailed measurements of the Fermi surface geometry and effective masses are presented which show a number of unusual properties associated with the magnetic structure and anisotropy. Measurements are compared with predictions of a band structure in which the f-electron is assumed to be local, interacting with the conduction electrons only through anisotropic Coulomb and exchange interactions. This model reproduces all the unusual features observed in the measurements and suggests that hybridization is not essential to describing the electronic properties of CeSb

No abstract available

[en] CeP and CeAs are characterized by low temperature measurements of the specific heat, the thermal expansion, the electrical resistivity and the magnetization of single crystal specimens. These physical properties are found to be very sensitive to crystal perfection and chemical composition in both the paramagnetic and the magnetically ordered state. In the intrinsically antiferromagnetic CeP, imperfections can give rise to a remanent magnetization below Tsub(N). (orig.)

[en] This chapter investigates the low-temperature lattice distortion and the magnetization of single crystals of DyS, DySe, HoS, and HoSe in steady fields up to 100 KOe and in pulsed fields up to 200 kOe. The magnetic behavior of the monochalcogenides is compared to that of the monopnictides using phase diagrams involving the cation-cation distances. The results indicate that DyS and DySe undergo a first-order transition to a pseudo-tetragonal (probably monoclinic) structure at the Neel point. The phase transition at the Neel temperature in HoS and HoSe is of second order. The magnetization behavior of HoS and HoSe corresponds to that of antimonide and bismuthide, and the magnetization curves of DyS and DySe are identical with that of DySb and DyBi. It is determined that DyS, DySe, HoS, and HoSe exhibit a type II antiferromagnetic order below the Neel temperatures of 36, 35, 19 and 20 K, respectively

No abstract available

[en] Pseudo-rhombohedral distortions below the Neel point of GdSb and GdBi are in fair agreement with estimates based on elastic constants of GdSb. In GdSe a second transition possibly transforms the rhombohedral cell into a monoclinic one. This transition was found to occur also in GdS and GdTe. (author)

[en] A rhombohedral distortion of the NaCl-type structure was found in the ferromagnetic temperature range of UTe, UTe₀sub(.)₅Sb₀sub(.)₅ and UTe₀sub(.)₂Sb₀sub(.)₈. In the latter compound an incommensurate magnetic structure exists between 140 K and the ordering temperature. In this temperature range the distortion was below the resolution limit of our diffractometer. The same is true for UTe₀sub(.)₁₅Sb₀sub(.)₈₅ and UTe₀sub(.)₁Sb₀sub(.)₉. (orig.)