Anisotropic p-f mixing mechanism explaining anomalous magnetic properties in Ce monopnictides. III. Paramagnetic state

Band calculations for 4f systems based on the dynamical mean field theory

Recent band calculations for Ce compounds based on the dynamical mean field theory (DMFT) are reported. The auxiliary impurity problem has been solved by a method named NCAf(2)vc, which includes the correct exchange process of the [Formula: see text] virtual excitation, the crystalline field splitting (CFS), and the spin-orbit interaction (SOI) of the self-energy. These are necessary features in the quantitative band theory for Ce compounds. The results of applications on Ce metal and Ce-monopnictides are presented.

Pressure-induced magnetic order in golden SmS

High pressure 149Sm nuclear forward scattering experiments have been performed on the nonmagnetic semiconductor SmS. We present the first clear evidence that the closure of the insulating gap at p(Delta) approximately 2 GPa coincides with the appearance of magnetic order. The pressure-induced magnetic phase transition has some first order character and suggests that the Sm ions are nearly trivalent at p(Delta). A Gamma(8) quartet crystal field ground state with a value of approximately 0.5 micro(B) for the samarium magnetic moment is inferred from our results. Considerable magnetic short range order is observed above the ordering temperature inferred from macroscopic measurements.

Direct observation of the modulation of the 4f-electron orbital state by strong p-f mixing in CeSb

Low-temperature x-ray diffraction experiment has been carried out to investigate the 4 f-electron state of the low carrier density system CeSb which shows complicated magnetic phase diagrams at low temperatures. The scattering pattern of the satellite peaks observed in the magnetically ordered state AFP3 is explained well by the model which takes into account both the lattice and charge modulations corresponding to the complex magnetic structure. The present result gives direct evidence for the strong modulation of the 4 f-electron orbital state in CeSb due to the combined effect of the strong p-f mixing and carrier localization.

Modulated Magnetic Phases in Rare Earth Metallic Systems

Neutron scattering has played a key role in the microscopic understanding of the static and dynamic properties of magnetic materials. Modulated magnetic structures first discovered in the late fifties can no longer be referred to as exotic; more than a hundred such phases have already been found in a variety of magnetic systems. Neutron and x-ray magnetic scattering have played a complementary role in the recent discovery and understanding of the modulated magnetic phases in rare earth metallic systems.