Hydrothermal crystallization in the systems Nd2O3(Nd(NO3)(3)center dot 6H(2)O)-CaCO3(BaCO3)-R-H2O (R = Na2CO3, K2CO3, NaCl, NH4Cl, NaHCO3, KHCO3, Na2CO3 + NaCl, Na2CO3 + NH4Cl, Na2CO3 + CO(NH2)(2)) was studied in the range 400-480 degrees C. All of the precipitates were found to contain crystalline NdOHCO3, NaNd(CO3)(2), and Nd-2(OH)(4)CO3. The lattice parameters of NdOHCO3 were refined, and a detailed scheme for its thermal decomposition was proposed.

Hydrothermal crystallization in the systems Nd2O3(Nd(NO3)3 ⋅ 6H2O)-CaCO3(BaCO3)-R-H2O (R = Na2CO3, K2CO3, NaCl, NH4Cl, NaHCO3, KHCO3, Na2CO3 + NaCl, Na2CO3 + NH4Cl, Na2CO3 + CO(NH2)2) was studied in the range 400–480°C. All of the precipitates were found to contain crystalline NdOHCO3, NaNd(CO3)2, and Nd2(OH)4CO3. The lattice parameters of NdOHCO3 were refined, and a detailed scheme for its thermal decomposition was proposed.

Single crystals of γ-Li 3 PO 4 have been grown from flux. The 4 × 8 × 9-mm crystals have the cleavage along the [010] and [120] directions. The anisotropy in ionic conductivity in the grown crystals, ((σ ‖ a )/(σ ‖ b ) = 2.5 and (σ ‖ a )/(σ ‖ c ) = 1.3), is explained by specific features of the γ-Li 3 PO 4 structure.

Crystals of Li 2 TiGeO 5 were obtained by solution-melt crystallization, and those of Na 2 TiGeO 5 were grown from a melt by pulling. The crystals are isostructural with the natisite mineral Na 2 TiSiO 5 . The crystal structure of Li 2 {TiOGeO 4 } was refined by X-ray diffraction analysis (a four-circle diffractometer, 2θ/θ scan mode, Mo K α radiation, θ max = 50°). The unit cell parameters are a = 6.614(4) Å and c = 4.435(4) Å; space group P 4/ nmm , Z = 2, ρ calcd = 3.67 g/cm 3 , R = 0.031, s = 1.128, wR ( F 2 ) = 0.071 (548 reflections with I ≥ 2σ I ). The ionic conduction in both crystals was found to be anisotropic in the temperature range 250–600°C;. At 400°C;, the conductivity values are 10 –4 to 10 –5 S/cm along the a axis and 10 –6 to 10 –8 (for Na 2 TiGeO 5 ) and 10 –7 to 10 –9 S/cm (for Li 2 TiGeO 5 ) along the c axis.

The crystal structure of the synthetic Ge-modification of the mineral natisite, Na 2 { TiOGeO 4 }, has been refined by X-ray diffraction method (a four-circle diffractometer, 2θ/θ scanning, Mo K α -radiation, θ max = 50°: a = 6.658(1), c = 5.161(1) Å, sp. gr. P 4/ nmm , Z = 2, ρ calcd = 3.58 g/cm 3 , R 1 = 0.030, s = 1.131, wR ( F 2 ) = 0.058 (352 reflections with I ≥2σ I ). The comparative crystallochemical analysis of the related (including hypothetical) phases with the anionic { MTO 5 } radicals ( M = Ti, V, Ge; T = Ge, Si, P) is performed with the aim of revealing a possible relationship between the composition and the structure type of the compounds.

The infrared reflectance spectra of two ${\mathrm{LaMnO}}_{3}$ crystals (pure and doped) have been measured at various temperatures between 300 and 10 K. The infrared active phonons of the two samples have been studied in detail and have been compared to recent lattice dynamics calculations. In the case of the undoped ${\mathrm{LaMnO}}_{3},$ the number of infrared active phonons agrees with the predictions of group theory. In contrast the phonon structures of the doped sample are broader and do not allow to identify all the expected lines.

Microwave magnetic resonance of close to stoichiometric antiferromagnetic LaMnO3 − δ was investigated. LaMnO3 − δ single crystals were grown and a series of samples with a small oxygen excess and deficiency was prepared. Residual magnetization was observed for all samples in the series. The maximum value of the residual magnetic moment in the series of samples obtained was 2.5% of the maximum possible value (4μB for each Mn ion). An absorption line, whose angular and frequency dependences cannot be explained on the basis of a previously proposed [S. Mitsudo, et al., J. Magn. Magn. Mater. 177–181, 877 (1998)] model of two-sublattice antiferromagnet with “easy axis” magnetic anisotropy (∥ b) and canting of the magnetic sublattices due to the Dzyaloshinski\(\overset{\lower0.5em\hbox{$\smash{\scriptscriptstyle\smile}$}}{l} \)-Moriya interaction, was observed in the experiments performed on all samples in a series as well as on specially prepared ceramic samples with the same composition. It was inferred that the low-frequency excitations in a system of ferromagnetic drops observed in [M. Hennion, et al., Phys. Rev. Lett. 81, 1957 (1998)] are observed in the experiment.

For the ferroelectric Li2Ge7O15 single crystal, the angular and temperature dependences of Li-7 NMR spectra and Li-7 spin-lattice relaxation rate were measured. The electric field gradient (EFG) tensor components on Li-7, quadrupole coupling constants (QCCs), and asymmetry parameters (eta(Q)) for crystallographically nonequivalent lithium positions Li(I) and Li(II) were determined. The second moment of Li-7 NMR line and the average Li-Li distance (3.23 angstrom) were calculated. The magnetically equivalent positions Li(1)-Li(4) with QCC = 78.1 kHz and eta(Q) = 0.94 belong to the Li(I) positions, while the magnetically nonequivalent positions Li(5)-Li(8) with QCC = 136.5, 142.8, 124.6, and 128.9 kHz and eta(Q) = 0.51, 0.46, 0.95, and 0.97, respectively, belong to the Li(II) positions. The ferroelectric phase transition at T-c = 283.4 K does not affect the Li-7 NMR parameters. In the vicinity of T-c, the spin-lattice relaxation mechanism, caused by spin-phonon interaction, changes. The Li(I) sublattice is more ordered in the directions of the EFG tensor principal components than the Li(II) sublattice.

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