Electronic and magnetic properties of the perovskitelike compounds of (La 1Ϫx Dy x ) 0.7 Ca 0.3 MnO 3 (0рx р0.5) have been studied by measuring electrical resistivity, magnetic susceptibility, magnetization, and magnetoresistance. All the compounds except xϭ0.5 show a ferromagnetic metal-paramagnetic insulator transition at T C . T C of the present compounds depend on the tolerance factor t and when t is larger than 0.913 the relations between T C and t are almost the same as those observed in the perovskitelike compounds previously examined, which contain rare-earth metal ions, such as Y 3ϩ , Pr 3ϩ , and Tb 3ϩ . When t is smaller than 0.907, a spin glass insulator appears at low temperature. This insulator is different from the ferromagnetic insulator that appears in the compounds containing light rare-earth metal ions, such as Pr 3ϩ and/or Y 3ϩ , but the same as that appears in the compound containing heavy rare-earth ions of Tb 3ϩ . It has been found that, when t takes a value between 0.907 and 0.913, the reentrant spin-glass state appears. Colossal magnetoresistance and tunneling magnetoresistance are clearly observed in the compounds. ͓S0163-1829͑98͒00545-1͔

No abstract

No abstract

No abstract

Pressure, density, and temperature data for H2O were obtained up to 260 GPa by using laser-driven shock compression technique. The shock compression technique combined with the diamond anvil cell was used to assess the equation of state models for the P-ρ-T conditions for both the principal Hugoniot and the off-Hugoniot states. The contrast between the models allowed for a clear assessment of the equation of state models. Our P-ρ-T data totally agree with those of the model based on quantum molecular dynamics calculations. These facts indicate that this model is adopted as the standard for modeling interior structures of Neptune, Uranus, and exoplanets in the liquid phase in the multi-Mbar range.