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تسجيل مستخدم جديدField induced spin ice like orders in spin liquid Tb$_2$Ti$_2$O$_7$
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We have studied the field induced magnetic structures in the spin liquid Tb$_2$Ti$_2$O$_7$, in a wide temperature (0.3$<$$T$$<$270 K) and field (0$<$$H$$<$7 T) range, by single crystal neutron diffraction with $bf{H}$ // [110] axis. We combined unpolarized neutron data with polarized ones, analyzed within the local susceptibility model. A ferromagnetic-like structure with $bf{k}$ = 0 propagation vector is induced, whose local order at low field and low temperature is akin to spin ice. The four Tb ions separate in $alpha$ and $beta$ chains having different values of the magnetic moments, which is quantitatively explained by taking the crystal field anisotropy into account. Above 2 T and below 2 K, an antiferromagnetic-like structure with $bf{k}$ = (0,0,1) is induced besides the $bf{k}$ = 0 structure. It shows a reentrant behavior and extends over a finite length scale. It occurs together with a broadening of the nuclear peaks, which suggests a field induced distortion and magnetostriction effect.
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