Q.F. Gu

A new triclinic modification of the pyrochlore-type KOS2O6 superconductor

A new modification of KOs2O6, the representative of a new structural type (Pearson symbol aP18, a=5.5668(1)A, b=6.4519(2)A, c=7.2356(2)A, space group P-1, no.2) was synthesized employing high pressure technique. Its structure was determined by single-crystal X-ray diffraction. The structure can be described as two OsO6 octahedral chains relating to each other through inversion and forming big voids with K atoms inside. Quantum chemical calculations were performed on the novel compound and structurally related cubic compound. High-pressure X-ray study showed that cubic KOs2O6 phase was stable up to 32.5(2) GPa at room temperature.

Compressibility of Al64Pd30.4Fe5.6

Abstract The stability of C2-Al64Pd30.4Fe5.6, an approximant phase to the icosahdral Al–Fe–Pd quasicrystal, has been investigated by high-pressure X-ray diffraction using a diamond-anvil cell and synchrotron radiation up to 24.30(1) GPa. The material is structurally stable within the framework of the experiment. The unit cell volume as a function of pressure follows a second-order Birch-Murnaghan equation of state with K0 = 169.5(2.5) GPa. This value is comparable to that of other quasicrystals and approximant phases containing Al and heavy transition metals.