Substitution effect of Ru5+ pyrochlores A2Ru2O7
Wei-tin Chen1,2*, Fang-Cheng Chou1,2
1Center for Condensed Matter Sciences, National Taiwan University, Taipei City, Taiwan
2Taiwan Consortium of Emergent Crystalline Materials, MOST, Taiwan
* presenting author:陳威廷,
Pyrochlore oxides A2B2O7 with rare earth A cation and transition metal B cation is one of the most extensively investigated system due to their wide variety of physical properties. For instance, pyrochlore oxides with A3+2Ru4+2O7 charge composition are of great interests owing to their fascinating magnetic behaviors. Many of these materials have a magnetic frustration system that the long-range ordering is suppressed, therefore novel short-range ordering behaviors, such as spin glasses, spin ice, spin liquids and some new physics are observed and attract considerable attention.

Drastic differences in magnetic and electrical nature are exhibited between A3+2Ru4+2O7 and A2+2Ru5+2O7 pyrochlore materials. With the high pressure synthesis techniques, Ru pyrochlores Ca2Ru2O7, Cd2Ru2O7 and Hg2Ru2O7 are stabilized and reported recently. These materials demonstrated interesting spin-glass, metal-insulator transitions and long-range magnetic ordering. With the equipped extreme condition synthesis apparatus, the series of Ru5+ pyrochlores are prepared, the substitution effect and their physical properties will be discussed.

Keywords: Pyrochlore, High pressure synthesis, Metal-insulator transition, 4d transition metal, Magnetic behavior