Year: 2003
Type: article
Abstract: We have studied spin relaxation in the spin ice compound ${\mathrm{D}\mathrm{y}}_{2}{\mathrm{T}\mathrm{i}}_{2}{\mathrm{O}}_{7}$ through measurements of the ac magnetic susceptibility. While the characteristic spin-relaxation time ($\ensuremath{\tau}$) is thermally activated at high temperatures, it becomes almost temperature independent below ${T}_{\mathrm{c}\mathrm{r}\mathrm{o}\mathrm{s}\mathrm{s}}\ensuremath{\sim}13\text{ }\text{ }\mathrm{K}$. This behavior, combined with nonmonotonic magnetic field dependence of $\ensuremath{\tau}$, indicates that quantum tunneling dominates the relaxational process below that temperature. As the low-entropy spin ice state develops below ${T}_{\mathrm{i}\mathrm{c}\mathrm{e}}\ensuremath{\sim}4\text{ }\text{ }\mathrm{K}$, $\ensuremath{\tau}$ increases sharply with decreasing temperature, suggesting the emergence of a collective degree of freedom for which thermal relaxation processes again become important as the spins become strongly correlated.
Source: Physical Review Letters
Institutions: Pennsylvania State University, Princeton University
Language: Latvian
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2055810797