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We have measured the angular distribution of gamma-rays in 208,209Po following the decay of the mass-separated isotopes 208,209At polarized at low temperatures in an iron host. Multipole mixing ratios were deduced for 14 and 9 gamma-ray transitions in 208Po and 209Po, respectively, and unambiguous spin-assignments were made for several levels in both nuclei.

Abstract: The fluoride-ion conductivity of the nonstoichiometric tysonite phases La0.95(Ba1−x Srx)0.05Fe2.95 (0⩽x⩽1) is investigated by impedance spectroscopy. Electrophysical measurements are performed in the frequency range 5–5105 Hz and temperature range 300–700 K. A discontinuity is observed in the temperature dependence of the conductivity at T c=410–430 K. The behavior of the temperature dependence of the electrical conductivity is explained within a transport model taking into account the migration of fluoride ions between different inequivalent structural sites. The maximum value of the conductivity at room temperature (293 K) is 210−4 Ω−1 cm−1 for the solid solution La0.95Sr0.05F2.95. The fluorine-ion conductivity in La0.95(Ba1−x Srx)0.05F2.95 single crystals is almost an order of magnitude larger than the value for the commercial solid electrolyte La0.992Eu0.008F2.992 (a fluorine-selective membrane) having a tysonite structure.

Temperature dependence of the angular distribution anisotropy of the 212·0 keV gamma-ray following the decay of153Tb oriented in a gadolinium host was measured at temperatures from 16 to 70 mK. Magnetic dipole hyperfine splitting parameter a0 for153Tb(Gd) and magnetic dipole moment of the153Tb ground state were estimated to be ¦a0¦?1·2×10-5 eV and ¦µ¦??3·1 nuclear magnetons, respectively.

Abstract: The fluorine-ion conductivity of anion-deficient solid solutions R 1−x CaxF3−x and R 1−x BaxF3−x having the tysonite (LaF3) structure was investigated by the impedance spectroscopy method. R 1−x CaxF3−x (R=La, Pr, Nd, Sm, Gd, Tb, Dy, Ho) and R 1−x BaxF3−x (R=La, Pr, Nd) single crystals were grown from the melt by the Bridgman-Stockbarger method. The electrophysical measurements were performed in the frequency range 5−5105 and temperature range 300–700 K. The temperature dependences of the electrical conductivity for the crystals studied is determined by the migration of fluorine anions along various structural positions. It is shown that, from the standpoint of increasing the conductivity of tysonite matrices RF3 (R=La, Pr, Nd), doping by CaF2 and BaF2 is less promising than SrF2.