Abstract
We have studied the evolution of the structural properties as well as the static and dynamic spin correlations of spin ice Ho2Ti 2O7, where Ho was partially replaced by non-magnetic La. The crystal structure of diluted samples Ho2-xLaxTi 2O7 was characterized by x-ray and neutron diffraction and by Ho LIII-edge and Ti K-edge extended x-ray absorption fine structure (EXAFS) measurements. It is found that the pyrochlore structure remains intact until about x = 0.3, but a systematic increase in local disorder with increasing La concentration is observed in the EXAFS data, especially from the Ti K edge. Quasi-elastic neutron scattering and ac susceptibility measurements show that, in x≤0.4 samples at temperatures above macroscopic freezing, the spin-spin correlations are short ranged and dynamic in nature. The main difference with pure spin ice in the dynamics is the appearance of a second, faster, relaxation process.
Original language | English |
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Article number | 235206 |
Journal | Journal of Physics Condensed Matter |
Volume | 20 |
Issue number | 23 |
DOIs | |
State | Published - Jun 11 2008 |
Externally published | Yes |