14 research outputs found
Low Temperature Spin Freezing in Dy2Ti2O7 Spin Ice
We report a study of the low temperature bulk magnetic properties of the spin
ice compound Dy2Ti2O7 with particular attention to the (T < 4 K) spin freezing
transition. While this transition is superficially similar to that in a spin
glass, there are important qualitative differences from spin glass behavior:
the freezing temperature increases slightly with applied magnetic field, and
the distribution of spin relaxation times remains extremely narrow down to the
lowest temperatures. Furthermore, the characteristic spin relaxation time
increases faster than exponentially down to the lowest temperatures studied.
These results indicate that spin-freezing in spin ice materials represents a
novel form of magnetic glassiness associated with the unusual nature of
geometrical frustration in these materials.Comment: 24 pages, 8 figure
Dirty Spin Ice: The Effect of Dilution on Spin Freezing in Dy2Ti2O7
We have studied spin freezing in the diluted spin ice compound Dy2-xYxTi2O7
where the non-magnetic Y ions replace the magnetic Dy ions on the frustrated
pyrochlore lattice. Magnetic a.c. and d.c. susceptibility data are presented
with an analysis of relaxation times for dilutions of x = 0, 0.1, 0.2, and 0.4.
Site dilution apparently decreases the relative number of spins participating
in the ice-like freezing near 16 K while leaving the freezing temperature
unchanged. Correspondingly the distribution of relaxation times associated with
the freezing is broadened only slightly with increasing dilution, suggesting
that the freezing process observed near T = 16 K involves local correlations
among the spins.Comment: 15 pages, 6 figures, submitted to Physical Review