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The effects of the oxygen deficiency on the electrical and magnetic properties of Sr 2 VO 4− δ were investigated. Single-phase samples of polycrystalline Sr 2 VO 4− δ with δ =0.18, 0.29 and 0.38 were synthesized by the solid state reaction in flowing hydrogen atmosphere. The crystal structure was determined by Rietveld analysis of X-ray diffraction data. All the samples were tetragonal at 298 K. With increase of δ, the lattice constant ‘a’ decreased and the lattice constant ‘c’ increased. Electrical resistivity measurements showed that all the samples were semiconductive with resistivity of about 1Ωcm at 298 K. Magnetic measurements showed that the magnetic properties of Sr 2 VO 4− δ system were strongly dependent on the oxygen deficiency δ. It was suggested that the non oxygen-deficient compound Sr 2 VO 4 ( δ =0) had no magnetic long-range order. As δ was increased, spin-glass-like behavior became evident at low temperatures and was overlapped by a long-range magnetic order with a transition temperature of ∼ 35 K for δ ≧ ∼ 0.2 . It was suggested that the long-range magnetic order was a canted antiferromagnetism with a small net magnetization.

A layered perovskite compound Sr3V2O7.01 was synthesized by heating mixtures of the constituent oxides at 1110°C in flowing hydrogen atmosphere. Rietveld analysis based on powder X-ray diffraction data shows that the compound has a tetragonal structure (I4/mmm) with a = 3.8331(7) A and c = 20.2459(6) A . The resistivity of the compound is 4.8 mΩ· cm at room temperature (300 K) and decreases with decreasing temperature down to 2 K. The magnetic susceptibility can be represented by a summation of temperature-independent and Curie-Weiss terms. The effective number of Bohr magnetons per vanadium atom is 0.37, which is considerably smaller than the free-ion value of 1.73 for V4+.

A new compound Sr4V3O9.60±0.01 has been synthesized by solid state reaction in flowing hydrogen atmosphere. Rietveld analysis based on X-ray diffraction data shows that it has a tetragonal structure (I4/mmm) with a = 3.8457(1) A and c = 27.9017(3) A . The resistivity of the compound is 1.4 mΩ · cm at room temperature (300 K) and decreases with decreasing temperature down to about 100 K followed by a slight increase with a further decrease of temperature. The magnetic susceptibility can be represented by a summation of temperature-independent and Curie-Weiss terms. The effective number of Bohr magnetons per vanadium atom is 0.37, which is considerably smaller than the free-ion values of 2.83 for V3+ and 1.73 for V4+. These results suggest that electron-electron interactions among the narrow π∗ band (t2g symmetry) electrons are important in this compound.

It is generally believed that the superconducting transition temperature ( T c ) of YBa 2 Cu 3 O x constantly increases as x increases up to 7. On the contrary, measurements of electric properties for epitaxially-grown thin films show that the T c is reduced near x =7. This reduction in T c reminds one of the property of La 2− y Sr y CuO 4 for high hole concentration, that is, the T c is reduced by excess hole doping. This over-hole-doping state may be an intrinsic feature of YBa 2 Cu 3 O ≈7 .

The nuclear spin-lattice relaxation time T1 of 45Sc and electrical and thermal resistivities in an itinerant electron ferromagnet Sc3In were measured in both ferromagnetic and paramagnetic states as a function of magnetic field strength. The observed magnetic field dependence of (T1T)-1 and negative magnetoresistivities in both states are explained very well by the self-consistently renormalized spin fluctuation theory in which the effect of magnetic field was taken into account. These experimental results support the spin fluctuation theory and suggest the importance of the effect of magnetic field on spin fluctuations.

Crotonothioamide, sorbothioamide, and cinnamothioamide undergo a threo selective aldol condensation via their enolates generated by a Michael addition of organometallics.

Nuclear spin-lattice relaxation time T1 of 91Zr in an itinerant electron ferromagnet ZrZn2 was measured in the whole temperature range including both ferromagnetic and paramagnetic states and at different magnetic fields. The experimental temperature dependences of (T1T)−1 are explained very well with the renormalized spin fluctuation theory in the presence of strong magnetic field.