Abstract
Synthesis and crystal structures are described for the compounds Ln2(Ti2-xLnx)O7-x/2, where Ln=Tb, Dy, Ho, Er, Tm, Yb, Lu, and x ranges from 0 to 0.67. Rietveld refinements of X-ray powder diffraction data indicate that in the Tb and Dy titanate pyrochlores, the extra Ln3+ cations mix mainly on the Ti4+ site with little disorder on the original Ln3+ site. For the smaller rare earths (Ho-Lu), stuffing additional lanthanide ions results in a pyrochlore to defect fluorite transition, where the Ln3+ and Ti4+ ions become completely randomized at the maximum (x=0.67). Initial magnetic characterization for the fully stuffed x=0.67 samples for Ln=Tb-Yb shows no long range ordering down to 2 K, and only partial saturation of the full expected magnetic moment under applied fields up to 5 T. In all of these Ln-Ti-O pyrochlores, the addition of magnetic Ln3+ in place of non-magnetic Ti4+ adds edge sharing tetrahedral spin interactions to a normally corner sharing tetrahedral network of spins. The increase in spin connectivity in this family of solid solutions represents a new avenue for investigating geometrical magnetic frustration in the rare earth titanate pyrochlores.
Original language | English (US) |
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Pages (from-to) | 3126-3135 |
Number of pages | 10 |
Journal | Journal of Solid State Chemistry |
Volume | 179 |
Issue number | 10 |
DOIs | |
State | Published - Oct 2006 |
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Condensed Matter Physics
- Physical and Theoretical Chemistry
- Inorganic Chemistry
- Materials Chemistry
Keywords
- Geometrically frustrated magnet
- Pyrochlore
- Pyrochlore to fluorite solid solution
- Rare earth titanate
- Stuffed pyrochlore
- Stuffed spin ice