%0 Journal Article
%T Mesoscopic correlations in Tb2Ti2O7 spin liquid
%A S. Guitteny
%A I. Mirebeau
%A P. Dalmas de R¨Ļotier
%A C. Colin
%A P. Bonville
%A F. Porcher
%A B. Grenier
%A C. Decorse
%A S. Petit
%J Physics
%D 2015
%I arXiv
%R 10.1103/PhysRevB.92.144412
%X We have studied the spin correlations with $\bf{k}$= ($\frac12$, $\frac12$, $\frac12$) propagation vector which appear below 0.4\, K in \tbti\ spin liquid by combining powder neutron diffraction and specific heat on Tb$_{2+x}$Ti$_{2-x}$O$_{7+y}$ samples with $x$=0, 0.01, -0.01. The $\bf{k}$= ($\frac12$, $\frac12$, $\frac12$) order clearly appears on all neutron patterns by subtracting a pattern at 1.2(1)\,K. Refining the subtracted patterns at 0.07\,K yields two possible spin structures, with spin-ice-like and monopole-like correlations respectively. Mesoscopic correlations involve Tb moments of 1 to 2 \mub\ ordered on a length scale of about 20 \AA. In addition, long range order involving a small spin component of 0.1 to 0.2 \mub\ is detected for the $x$= 0 and 0.01 samples showing a peak in the specific heat. Comparison with previous single crystals data suggests that the ($\frac12$, $\frac12$, $\frac12$) order settles in through nanometric spin textures with dominant spin ice character and correlated orientations, analogous to nanomagnetic twins.
%U http://arxiv.org/abs/1506.07604v2