Dynamics of a permanent magnet levitating above a high-Tc superconductor

The oscillation modes of a small spherical permanent magnet (1.7 mm diameter) above a flat high-T_c superconductor are investigated. From the attenuation and nonlinearity of the vertical oscillation we obtain the viscosity of the vortex lattice and the onset of hysteretic damping, which indicates depinning of flux lines. The shape of the potential well in which the magnet floats, rotates, and oscillates is found to depend on the magnetic history of the superconductor.     

Investigation of valence band structures in Cu-Pd alloys

With the use of a HP 5950 A spectrometer X-ray photoelectron spectra (XPS) of valence band were obtained for Cu-Pd alloys and the density of electron states was calculated by the coherent potential method. It is found that d-resonance states of Pd are present in the alloys containing a high percentage of copper but there are no apparant d-resonance states of Cu in the alloys containing a high percentage of palladium.     

Use of X-ray photoelectron and Mössbauer spectroscopies in the study of iron pentacyanide complexes

A number of iron pentacyanide complexes of the Na_itn [Fe(CN)₅X] type have been synthesized. The compounds have been examined by X-ray photoelectron (ESCA) and Mössbauer spectroscopies. The influence of the nature of ligand X upon the properties of iron- (II) pentacyanide complexes has been studied. The donor properties of dinitrogen as a ligand have been compared with those of other nitrogen-containing ligands. A correlation has been established between the ESCA and Mössbauer data.     

X-ray band spectra and electronic structure of carbides and nitrides of zirconium,niobium and molybdenium

The L- and M-emission spectra of Zr, Mb and Mo carbides and nitrides have been studied. The spectra were excited by primary techniques, it is concluded that the valence bands of these carbides and nitrides consist of two sub-bands: a sub-band of states which participate in covalent bonds and a sub-band of states which share in the formation of metallic bonding and account for the metallic properties of these phases.     

Theoretical investigation of the structure of X-ray photoelectron spectra of crystals

In the one-electron approximation general relations are obtained which determine the X-ray photoemission intensity from mono- and poly-crystalline solids. To describe the excited electron states plane waves and orthogonalized plane waves have been used. It is shown that consideration of orthogonalization terms is important when photoionization cross-sections of valence electrons are to be calculated. Results are discussed using the examples of transition metals, noble metals, semiconductors and dielectrics possessing the diamond and zinc-blende structure. The spectra from poly-crystals and single crystals of transition metals can differ markedly, but in the case of dielectrics the difference is small. Calculated X-ray photoelectron spectra of crystals are in good agreement with experimental data. To obtain detailed information of the spectrum structure, especially when transition metals are considered, the many-electron effects must be taken into account.     

X-ray Kβ-and L2,3-emission bands of pure silicon and silicon in ZrSi compounds

The intensity distribution of the K_β-and L_2,3-emission bands of pure silicon and silicon in ZrSi₂, Zr₃Si₂, Zr₅Si₃ and Zr₃Si are investigated. Some of the aspects of the electronic structure of these compounds are discussed.