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X. Wan

Publications and source records attributed to X. Wan.

4 recordsLinked to original sources
arXiv2008

Competition between Kondo and RKKY exchange couplings in Pu{1-x}Am{x} alloys

To clarify the role of the Kondo effect in screening local magnetic moments of Plutonium 5f--electrons as well as its competition to the RKKY interactions we use a combination of density functional theory with static Hartree Fock and dynamic Hubbard 1 approximations to calculate the strength of both the Kondo exchange, J_K, and of the RKKY exchange, J_RKKY, couplings for Pu{1-x}Am{x} system as a function of x. We find that J_K increases despite the atomic volume gets larger with the Am doping due to unexpected enhancement of hybridization between f and conduction electrons in the vicinity of the Fermi level. At the same time, the RKKY exchange is shown to reduce smoothly with increasing x. Our results imply that the Kondo effect should be robust against the increase in interatomic spacing of this alloy.

cond-mat.str-el↗
arXiv2000

Phase shift effects on the second moment and skewness of the field profiles obtained by the muon spin relaxation technique

Recent high transverse field muon spin relaxation (TF-uSR) experiments performed on Bi2212 single crystals show that the phase parameter extracted from individual histogram, an indication of the angle between the muon's initial polarization direction and the detector direction, is temperature dependent. This phase shift effect, probably due to the electronic or initial polarization instability at a time interval comparable with the muon spin precession period, will affect the second moment and skewness of the field profiles. The proper data analysis procedure is discussed to correct this phase shift effect, which is important on the quantitative interpretation of the first order transition or melting transition in the Bi2212 mixed state.

cond-mat.mtrl-sci↗
arXiv1999

Cauchy magnetic field component and magnitude distribution studied by the zero-field muon spin relaxation technique

Zero-field muon spin relaxation (ZF-$μ$SR) data for dilute spin magnetic systems have been widely interpreted with what is called a Kubo-Toyabe form based on a Lorentzian distribution of local field components. We derive here the proper magnetic field \textit{magnitude} distribution using independent and uncorrelated \textit{component} distributions. Our result is then compared to the previously accepted formula for ZF-$μ$SR. We discuss the origins of the magnetic field component and magnitude distributions. Further we found that after rescaling the magnetic field, the differences that are amenable to experimental examination are quite small, although the interpretations behind them are quite different.

cond-mat.mtrl-sci↗