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Polycristalline samples of cobalt, nickel and manganese tartrates were studied using impedance measurements and x-ray powder diffraction in the temperature range 213-300 K. The dependence of the real part of the dielectric permittivity for manganese tartrate showed a peak at about 250 K, which can be interpreted in favour of phase transition. To support this view we have report the XRD patterns a different temperatures around 250 K.

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We report here on the dielectric properties (dielectric constant, ɛ′ and dielectric losses ɛ″), magnetic properties (μ′ and μ″), infrared spectroscopic, thermal studies (thermogravimetric analysis (TGA)), differential thermogravimetry (DTG) and differential scanning calorimetry (DSC) and X-ray diffraction (XRD) for the polycrystalline powdered samples of manganese tartrate MnC4H4O6·2H2O obtained by diffusion of manganese ions through silica gel impregnated with tartaric acid. The aforementioned properties are used as a probe for the detection and study of the different transitions that have been found in this salt. Energy dispersive analysis of X-rays (EDAX) confirmed the presence of manganese. X-ray diffraction data giving 2gq, intensity andd-values are reported for the first time. Infrared wavelengths in the range 500–4000 cm−1and the description of peaks recorded for the material are given. Results of thermal analysis indicated that the material is thermally unstable. Dielectric and magnetic measurements were determined in the frequency range of 45 MHz to 2 GHz.

We reviewed the observational features supporting the view that azimuthal transport of solar flare particles takes place at the level of the solar corona, and not in the interplanetary medium. A brief description is given of models regarding longitudinal particle transport, in terms of their ability to explain the corresponding observational phenomena. Finally, a model with multiple particle emission phases is proposed, in terms of two coronal azimuthal transport steps, on the basis of the dynamical and static features of the coronal magnetic field, respectively.

By studying the data from the worldwide neutron monitor network the spectra of most of the solar proton events in cycles 19–20 have been determined. These spectra are best represented by a power law with an upper cutoff Rm. This holds over a wide range in energy or rigidity. For the events examined Rm had values between 3 GV and 20 GV. It is shown that there is no correlation between Rm and the amplitude of the events.

Experimental values for the complex dielectric permittivity of Triglycine Selenate single crystal are reported, on both sides of the ferroelectric Curie temperature, covering the. audiofrequency range. The dielectric losses and the real part of the susceptibility follow the empirical relation: χ''(ω) ∼ χ' (ω) ∼ ωn-1, according to the Jonscher Universal law. The dynamic contributions of domains have been evaluated. The obtained values for the n index show a discontinuity in the ferro-paraelectric transition.

Experimental values are reported for the complex dielectric permittivity, ε (ω), of single crystal Deuterated Triglycine Sulphate (DTGS) at temperatures on both sides of the ferroelectric Curie temperature Tc, covering the audio and subaudio frequency range, (102 to 105 and 10-4 to 1 Hz). In the audio frequency range, in contrast with the strong typical ferroelectric dispersion in the GHz region, the dielectric losses and the real part of the susceptibility X (ω) = ε (ω) - ε∞ follow the empirical relation X'' (ω) ∼ ωn-1 which gives a frequency independient ratio, according to the Jonscher universal law for the dielectric response X''/X' = cot (nII/2). However, in the subaudio frequency region we find that the dielectric loss fits the empirical relation X'' (ω) ∼ ω when ω → 0. The experimental results are discussed.

The effect of an ac applied field on the values of the critical exponents and on the ferroelectric temperature transition in TGS is presented. The determination of the critical gap exponent Δ'3 by capacitance measurements was also made. The results obtained are discussed in terms of the ideal molecular field theory.

The temperature dependence of the dielectric constant and the spontaneous polarization has been investigated for BaTiO3 crystals doped with Co. Experimental evidence about diffuse phase transitions (DPT) in this compound is made.