Critical slowing down in the geometrically frustrated pyrochlore antiferromagnet Gd2Ti2O7

Abstract

Longitudinal-field muon spin relaxation experiments have been carried out in the paramagnetic state of singlecrystal Gd2Ti2O7 just above the phase transition at Tm = 1.0 K. At high applied fields the exponential relaxation time T1 is proportional to field, whereas T1 saturates below a crossover field Bc that is ∼2.5 T at 1.5 K and decreases as Tm is approached. At low fields the relaxation rate increases markedly as the freezing temperature is approached, as expected for critical slowing down of the spin fluctuations, but the increase is suppressed by applied field. This behavior is consistent with the very long autocorrelation function cutoff time implied by the low value of Bc.

Unstable spin-ice order in the stuffed metallic pyrochlorePr2+xIr2−xO7−δMacLaughlin1, Bernal2, Shu3 et al. 2015Phys. Rev. BSelf Cite331190View full textAdd to dashboardCite

“…This is the case in Pr 2+x Ir 2−x O 7−δ . Time-field scaling of a relaxation function has been interpreted as evidence for a zerofrequency divergence of the noise power spectrum associated with "glassy" spin dynamics [49][50][51][52] or proximity to a quantum critical point, with or without structural disorder [53,54]. These associations are valid only if the applied field does not modify the spin dynamics, but merely sweeps the µ + precession frequency through the noise power spectrum.…”