Absence of anomalous negative lattice-expansion for polycrystalline   sample of Tb2Ti2O7
  High resolution X-ray powder-diffraction experiments on a well-characterized polycrystalline sample of the spin liquid Tb2Ti2O7 reveal that it shows normal positive thermal-expansion above 4 K, which does not agree with the intriguing anomalous negative thermal-expansion due to a magneto-elastic coupling reported for a single crystal sample below 20 K. We also performed a Rietveld profile refinement of a powder-diffraction pattern taken at a room temperature, and confirmed that it is consistent with the fully ordered cubic pyrochlore structure. 
Kazuki Goto, Hiroshi Takatsu, Tomohiro Taniguchi, and Hiroaki Kadowaki
cond-mat.str-el cond-mat.dis-nn