High-resolution photoacoustic spectra of trinitrate-bis[N-(2- pyridylmethylene)-N′-benzoyl-hydrazine]R(III), (R = La, Cc, Pr), and binitrato-bis[N-(2-pyridylmethylene)-N′-benzoyl-hydrazine]R(III) nitrate (R=Y, Nd, Eu, Yb, Tb, Gd, Ho, Dy, Er) complexes, in the visual region, were studied for powder samples. Very intense photoacoustic spectra of various shapes were attributed to the intraligand transitions of the π → π* type located mainly on the C=N group and the n → π* transitions located on the carbonyl group. The intensity of these transitions essentially depends on the type of rare earth ions. The existence of f-f electron transitions could influence the relaxation processes, which play an important role in intensity determination of the above transitions. For many investigated samples the energy levels of excited states of rare earth ions were identified (f-f electron transitions). The radiation energy for some of the rare earth ions were compared with the d-d electron transitions of certain coppcr(II) organometallic complexes, which are very important in biogenic systems. The correlation between ions with localized and extended wave functions is suggested.

{Single crystal of erbium doped La3Ga5.5Ta 0.5O14 grown by the Czochralski method have been investigated by electron paramagnetic resonance and dielectric spectroscopy methods. Dielectric permittivity ε measurements performed in 90-440 K temperature range have shown negligible dispersion for 1 kHz - 1 MHz frequencies and a Curie-Weiss type behaviour with C = 47700 K and θ = -340 K. Electron paramagnetic resonance studies have revealed the presence of two different paramagnetic, monoclinic centres. The calculated g factor values are: g1 = 1.449

Glass ceramics of the composition (Bi0.8Pb0.2) 4Sr3Ca3Cu4O8 prepared by the melt quenching technique and the crystalline phases produced by the rapid thermal annealing have been studied by electrical resistivity and electron paramagnetic resonance (EPR) measurements in the temperature range from liquid helium up to room temperature. The concentration of the EPR active Cu 2+ paramagnetic centers decreases as conductivity increases for the glass ceramics and disappears alter crystallization and the growth of superconducting phases, similar to bulk high-Tc,. superconductors. The EPR spectra of both glass and crystallized ceramics after short-time annealing indicate the coexistence of Cu2+ paramagnetic ions and the exchange coupled clusters.

The neutron diffraction patterns of Mg2FeV3O 11-δ compound at various low temperatures have been investigated. No magnetic ordering was observed in the investigated temperature range down to 10K. These materials have been formed in the triclinic space group but there are specific differences in the positions of atoms as compared to previously determined from XRD method. The iron(III) ions are distributed non-statistically with magnesium(II) ions and this could be responsible for some differences in the structure of the above sample. The method of sample preparation, in particularly thermal annealing processes could be responsible for the differences.

Surface deformation and ferroelectric domain switching induced by a force microscope tip on a La-modified PbTiO3 thin film was studied. Polarization switching of the domains comprising the deformed region demonstrated the possibility of using scanning force microscopy (SFM) as a nanoscale tool for imaging phase transitions. It was found that if loading forces are higher than a threshold value, thin film characterization becomes invasive.

Multiwall carbon nanotubes were studied by dc magnetization and electron spin resonance (ESR) measurements. Hole doping is inferred from both the high-field dc susceptibility and ESR parameters complying favorably with the band model of two-dimensional graphite. Paramagnetic deviations are evinced on the diamagnetic susceptibility at weak fields and low temperatures, conforming qualitatively with the Aharonov-Bohm effect on the energy gap for magnetic field parallel to the tube axis. Comparison with theoretical predictions for ensembles of carbon nanotubes reveals appreciable differences, indicative of the diverse distribution of nanotubes as well as the presence of active doping. © 2003 The American Physical Society.

Influence of water molecule coordination on the magnetic properties of polyamine copper dinitrate complexes was studied. It was found that the magnetic coupling between Cu2+ ions strongly depends on the presence of water molecules in the crystal structure. Electron paramagnetic resonance (EPR) measurements showed considerable temperature dependence of the Lande′ splitting factors and resonance linewidths for both complexes at low temperatures.

A study was performed on the optical nanowriting on azobenzene side-chain polymethacrylate thin films using near-field scanning optical microscopy (NSOM). The optical storage mechanism in azobenzene side-chain polymers is based on the isomerization cycles of the azobenzene side-chains between their cis and trans forms. The optical anisotropy was detected by coupling the red light at 690 nm with modulated polarization to the NSOM aperture.

Conduction electron spin resonance is employed to study the interplay of the electronic and structural properties in the normal state of Mg1-xAlxB2 alloys as a function of Al-doping for 0 ≤ x ≤ 1. The x-dependence of the spin susceptibility reveals considerable reduction of the total density of states N(EF) with increasing Al concentration, complying with theoretical predictions for a predominant filling effect of the hole σ bands by electron doping. The CESR linewidth exhibits significant broadening, especially prominent in the high-Al-content region, indicative of the presence of enhanced structural disorder, consistent with the presence of compositional fluctuations.