Pyrochlore is a more generic term for the pyrochlore crystal
structure (Fd-3m). The more general crystal structure describes
materials of the type A2B2O6 and A2B2O7 where the A and B species
are generally rare-earth or transition metal species; e.g. Y2Ti2O7.
The pyrochlore structure is a super structure derivative of the simple
fluorite structure (AO2 = A4O8, where the A and B cations are ordered
along the <110> direction. The additional anion vacancy resides in the
tetrahedral intersticy between adjacent B-site cations. These systems
are particularly susceptible to
geometrical frustration
and novel magnetic effects.
The pyrochlore structure shows varied physical properties ranging from electronic
insulators, La2Zr2O7, ionic conductors, Gd1.9Ca0.1Ti2O6.9, metallic conductivity,
Bi2Ru2O7-y, Mixed Ionic and Electronic Conductivity,
spin ice systems Dy2Ti2O7,
spin glass systems Y2Mo2O7 and superconducting materials
Cd2Re2O7. Reference:
Text: Wikipedia
Neutron Scattering on KOs2O6 powder Authors: Götz Schuck, Janusz Karpinski, Zbigniew Bukowski Conference: 2008 Swiss Physical Society - MaNEP meeting, Genève, March 26-27, 2008