Magnetic hyperfine interaction of Br in Ni

The magnetic hyperfine splitting frequency of ⁸²BrNi in an external magnetic field of 0.2 T has been measured by NMR-ON method at 8 mK. The centre of resonance frequency was determined to be 18.7(2) MHz. With the known g-factor of g(⁸²Br)= 0.3254(1), the hyperfine field of ⁸²BrNi was deduced as B_hf(⁸²BrNi)= 7.34(8) T. The measured value is compared with the calculated value based on band structure using bonding states. This revised version was published online in August 2006 with corrections to the Cover Date.     

High-precision quantitative atomic-site-analysis of functional dopants in crystalline materials by electron-channelling-enhanced microanalysis

Knowledge of the location and concentration of impurity atoms doped into a synthesized material is of great interest to investigate the effect of doping. This would usually be investigated using X-ray or neutron diffraction methods in combination with Rietveld analysis. However, this technique requires a large-scale facility such as a synchrotron radiation source and nuclear reactor, and can sometimes fail to produce the desired results, depending on the constituent elements and the crystallographic conditions that are being analysed. Thus, it would be preferable to use an element-selective spectroscopy technique that is applicable to any combination of elements. We have established a quantitative method to deduce the occupation sites and their occupancies, as well as the site-dependent chemical states of the doped elements, using a combination of transmission electron microscopy (TEM), energy-dispersive X-ray (EDX) spectroscopy, and electron energy-loss spectroscopy (EELS). The method is based on electron channelling phenomena where the symmetries of the Bloch waves excited in a crystal are dependent on the diffraction condition or incident beam direction with respect to the crystal axes. By rocking the incident electron beam with a fixed pivot point on the sample surface, a set of EDX/EELS spectra are obtained as a function of the beam direction. This is followed by a statistical treatment to extract the atom-site-dependent spectra, thereby quantitatively enabling the estimation of the site occupancies and chemical states of the dopants. This is an extension of the ‘ALCHEMI’ (Atom Location by Channelling Enhanced Microanalysis) method or ‘HARECXS/HARECES’ (High Angular Resolution Channelled X-ray/Electron Spectroscopy), and we further extended the method to be applicable to cases where the crystal of interest contains multiple inequivalent atomic sites for a particular element, applying the precise spectral predictions based on electron elastic/inelastic dynamical scattering theory. After introduction of conceptual aspects of the method, we describe the extension of the method together with the development of the theoretical calculation method. We then demonstrate several useful applications of the method, including luminescent, ferrite, and battery materials. We discuss the advantages and drawbacks of the present method, compared with those of the recently developed atomic column-by-column analysis using aberration-corrected scanning TEM and high-efficiency X-ray detectors.     

Specific heat of 1T-Ta0.93Ti0.07S2 in the Anderson localized states

The specific heat of 1T-Ta_0.93Ti_0.07S₂ in the Anderson localized states has been measured from 0.2 to 5.0 K in magnetic fields up to 60 kOe. Below 3.5 K, a Schottky type excess specific heat was observed, depending on the magnetic field. This excess specific heat is explained on the basis of both the Coulomb interactions between different Anderson localized states as well as in the same state.     

TE-TM Mode Converter Using Optically Active Polymer

A novel TE-TM mode converter using optically active polymer: poly-1-menthylmethacrylate (PMtMA) was studied theoretically and experimentally. In a three-layered slab waveguide consisting of the PMtMA core layer on a fused quartz substrate, a low-loss TE₀-TM₀ mode conversion with an efficiency of 60 to 70% was easily obtained for the first time at a wavelength of 441.6 nm. The method to achieve a phase-matched operation of this polymer TE-TM mode converter was also discussed.     

Nuclear magnetic resonance on oriented76,77,82Br in Fe

Nuclear magnetic resonance on oriented^76,77,82BrFe has been measured using recoil-implanted samples. The magnetic hyperfine splitting frequency of⁸²BrFe in a zero external magnetic field has been determined to be 201.90(3) MHz. The resonances of⁷⁶BrFe and⁷⁷BrFe were also observed in an external magnetic field of 0.2 T asv(⁷⁶BrFe)=340.9(3) MHz andv(⁷⁷BrFe)=403.5(2) MHz. With the known values of theg-factors, the hyperfine fields have been deduced:B _HF(⁸²BrFe)=81.397(27) T,B _HF(⁷⁶BrFe)=81.38(7) T. Theg-factor of⁷⁷Br was determined to be |0.6487(4)|.     

On some property of an irreducible subalgebra of the general linear Lie algebra gl(n,R)

Summary A subalgebrag ofgl(n, R) which admits no proper invariant subspace in Rⁿ and contains a subalgebra of a special kind is studied. It is concluded that only four cases are possible if n is even, and only two if n is odd. To Enrico Bompiani on his scientific Jubilee