Kondo screening of the spin and orbital magnetic moments of Fe impurities in Cu

We use x-ray magnetic circular dichroism to evidence the effect of correlations on the local impurity magnetic moment in an archetypal Kondo system, namely, a dilute Cu:Fe alloy. Applying the sum rules on the Fe L2,3 absorption edges, the evolution of the spin and orbital moments across the Kondo temperature are determined separately. The spin moment presents a crossover from a nearly temperature-independent regime below the Kondo temperature to a paramagneticlike regime above. Conversely, the weak orbital moment shows a temperature-independent behavior in the whole temperature range, suggesting different Kondo screening temperature scales for the spin and orbital moments

Kondo Insulator: p-wave Bose Condensate of Excitons

In the Anderson lattice model for a mixed-valent system, the $d-f$ hybridization can possess a $p$-wave symmetry. The strongly-correlated insulating phase in the mean-field approximation is shown to be a $p$-wave Bose condensate of excitons with a spontaneous lattice deformation. We study the equilibrium and linear response properties across the insulator-metal transition. Our theory supports the empirical correlation between the lattice deformation and the magnetic susceptibility and predicts measurable ultrasonic and high-frequency phonon behavior in mixed-valent semiconductors.Comment: 5 pages, 3 encapsulated PostScript figure

Modern microwave methods in solid state inorganic materials chemistry: from fundamentals to manufacturing

No abstract available

Evidence for Modification of the Electronic Density-of-States by Zero-Point Lattice Motion in One-Dimension - Luminescence and Resonance Raman Studies of An Mx Solid

Luminescence spectra, both emission and excitation, and the excitation dependence of the resonance Raman spectra, have been measured for the quasi-one-dimensional charge-density-wave material [Pt(en)2][Pt(en)2Cl2](ClO4)4, en = 1,2-diaminoethane. While the luminescence experiments show the existence of tail states at low temperature in the band gap region, the Raman measurements conclusively demonstrate that this tail does not arise from ordinary static structural disorder. These results can be explained by considering the zero-point motion of the lattice

Kondo screening of the spin and orbital magnetic moments of Fe impurities in Cu

We demonstrate by analysing a model dilute Kondo alloy that x-ray magnetic circular dichroism (XMCD) is able to evidence the Kondo regime. The temperature evolution of the d spin and orbital magnetic moments of Fe impurities in highly diluted Cu:Fe alloys is measured. XMCD is also a unique technique which enables the direct and separate measurement of the spin and orbital moments of a Kondo impurity

Breakdown of the electron-spin motion upon reflection at metal-organic or metal-carbon interfaces

Spin-polarized electron scattering experiments on different metal-organic and metal-carbon interfaces are performed. A completely unexpected behavior of the spin-motion angles as well as of related quantities as a function of the organic layer or carbon coverage is observed. In fact, by deposition of organic molecules or carbon onto ferromagnetic as well as nonmagnetic metal surfaces in the submonolayer thickness range, the electron reflection amplitude, i.e., both the reflectivity and the reflection phase, become spin independent. Our findings show that this behavior is a very general phenomenon which is independent of the electron energy and the choice of the metal as well as of the organic molecules and thus does not depend on the choice of the specific interface