Concentration dependences of dielectric transitions (Tc1, Tc2, Tc3), superconductive transition TS and isomeric shift of the Mossbauer line δ have been studied on the solid solutions BaPbO3-BaBiO3 using Sn119 nuclei. It is found that the same oxide can show ferroelectric or superconductive properties depending on temperature. The minima on Tc2 curves correlate with maxima on TS and δ curves. Other experimental data are discussed.

Moesbauer measurements on /sup 119/Sn impurity nuclei in BaPbO/sub 3/--BaBiO/sub 3/ ceramic samples with composition x = 0, 0.08, 0.10, 0.15, 0.20, 0.25, 0.30, 0.38, 0.47, 0.60, 0.75 and 1.00 are reported. Correlation between the isomeric. (AIP)

Complex investigations of compounds with the perovskite type A2BReO6 (A=Ba, Sr; B=Li, Mg, Zn, Ca, Mn, Fe, Co, Ni) and PB2BReO6 (B=Mg, Fe, Co, Ni) were performed.

The use of resonance detectors in Mössbauer spectroscopy allows a reliable determination of the nonresonant background level, which should be taken into account when the absolute value of the Mössbauer fraction (ƒ′) is needed. Simple formulae for finding the factors ƒ′ from the areas of the experimental spectra have been derived. Room-temperature values of ƒ′ for 23.8 keV γ-rays of 119Sn in some tin compounds have been obtained using the resonance detectors: ƒβ−Sn′ = 0.057; ƒ′SnO2=0.55; ƒ′CaSnO3=0.57; ƒ′BaSnO3=0.591

A number of compounds with the hexagonal barium titanate structure, namely Ba2FeSbO6 and Ba3Fe2BO9 (B = Re, Te, W, Mo) are studied using neutron diffraction and high-temperature X-ray analysis, dielectric measurements at low and superhigh frequencies, electron spin resonance, Mössbauer effect, and magnetic measurements. Results of the study reveal the spontaneously polarized state in these compounds which can be classified as new seignette-magnets. [Russian Text Ignored].

Complex investigations are made (neutron diffraction study, high temperature X-ray analysis, dielectric measurements at low and superhigh frequency ranges, resonance (ESR and Mössbauer effect) and magnetic measurements) on the known compounds A2BReO6 (A = Ba, Sr; B = Li, Mg, Ca, Mn, Fe, Co, Ni) and under high pressure synthesized compounds Pb2BReO6 (B = Mg, Fe, Co, Ni) with the perovskite-type structure. The total sum of the results shows the presence of a spontaneously polarized state in the investigated compounds. Seven new seignettomagnets are found. [Russian Text Ignored].

Calculations have been made of Mössbauer absorption spectra, taken by means of resonance detectors. Parameters of the spectra have been correlated with effective thickness of the source, absorber and detector and the widths of their spectral lines. The effect of a shift between the emission spectrum and the detector line has been considered and correction formulas obtained.

Mossbauer study of polycrystallic BaTi03 (I), PbTi03 (11) and PbZr03 (111), doped with 1 at.% of radioactive Sn1 19m was performed. The Mossbauer fraction f and the chemical shift δ of the resonance γ-rays were measured in the temperature range 77-1000°K. In the vicinity of the phase transitions the data were taken in great detail.