The interplay between surface morphology and ferroelectric domain structure on triglycine sulfate (TGS) (010) cleavage faces is investigated by voltage-modulated scanning force microscopy in the dynamic contact mode. A resonance enhancement method is exploited to increase imaging contrast and sensitivity to slight variations of surface polarity. Evidence of electric contrast of the structural nuclei forming due to surface reconstruction of the TGS cleavage face, is provided, further supported by second harmonic measurements. Lateral growth at ambient conditions and high mobility of the surface nuclei relative to the spontaneous ferroelectric domain motion after cooling from above Tc is detected. Surface charge screening by the conductive liquid film that condenses on the cleavage surface and its interface dynamics are suggested to determine the kinetics of surface nuclei during ferroelectric domain coarsening and the formation of a zig-zag domain boundary. © 2001 Elsevier Science B.V. All rights reserved.

Photoacoustic and electron paramagnetic resonance (EPR) spectroscopies have been applied to resolve the electronic structure in powder polycrystalline samples of three biogenic polyamine copper complexes, spermine copper dinitrate, aqua norspermine copper dinitrate, and homospermine copper dinitrate. The fine structure of the intense absorption band in the photoacoustic spectra is assigned to the d-d transitions between the crystal field split levels of copper ions, that cannot be discriminated in the UV/vis solution absorption spectra. Combination with the EPR results allows one to probe the variation of the electronic properties and bonding interaction at the copper site, consistent with the structural data for the crystalline complexes and further supports the reliability of the photoacoustic method to resolve the d-d transition band. A dominant contribution of the in-plane ligand field due to equatorial nitrogen atoms is deduced for the complexes of polyamines with copper salts. © 2001 American Institute of Physics.

Ferroelectric domain kinetics on cleaved triglycine sulfate, quenched at different temperatures in the ferroelectric phase, is investigated in situ by scanning force microscopy in the dynamic contact mode. Thermally activated domain growth and dynamic scaling, in accordance with theoretical predictions for quenched disorder due to random-bond defects, is inferred from the temporal evolution of the spatial correlation functions and the related characteristic length scale.

Mechanical resonance modes of the scanning force microscope (SFM) cantilever in contact conditions provide contrast enhancement in the imaging of surface charges when using voltage modulation techniques tuned to such resonances. Extensions of the method were made as regards the lateral (twisting) and frontal (buckling) modes of the cantilever, as well as the enhanced second harmonic detection of voltage-modulated response at resonance and near-resonance detection in the SFM tapping mode. As an example of application, vibration spectra and images taken on a triglycine sulfate (TGS) single crystal are discussed. © Springer-Verlag 2001.

Concentrated polycrystalline DyBa2Cu3O6+cursive Greek chi compounds are studied by X-band EPR spectroscopy. A broad resonance line due to the highly anisotropic EPR spectrum of Dy3+ ions is identified on several specimens at low temperatures. Powder simulation of the EPR spectra complies with the ground Kramers doublet predicted by crystal field analysis of Dy3+ ions. Calculations of the second and fourth moments of the resonance lines due to the dipole-dipole interactions of Dy3+ indicate the presence of substantial exchange narrowing of the dipolar-broadened EPR linewidth.