Dynamic Properties of a Diluted Pyrochlore Cooperative Paramagnet(TbpY1−p)2Ti

Abstract

Investigations of the spin dynamics of the geometrically frustrated pyrochlore (Tb(p)Y(1-p))2Ti2O7, using muon spin relaxation and neutron spin echo, as a function of magnetic coverage p, have been carried out. Our major finding is that paramagnetic fluctuations prevail as T-->0 for all values of p, and that they are sensitive to dilution, indicating a cooperative spin motion. However, the percolation threshold pc is not a critical point for the fluctuations. We also find that the low temperature spectral density has a 1/f behavior, and that dilution slows down the spin fluctuations.

Frustrated rare earth magnetism: Spin glasses, spin liquids and spin ices in pyrochlore oxides

“…The "cooperative paramagnetic" picture is re-enforced by spin dynamics studies of a systematically diluted system, (Tb 1−x Y x ) 2 Ti 2 O 7 , where x is varied from 0 to 0.21 (below the percolation limit of 0.39). Both SR and NSE data show a strong dependence of spin dynamics on x but there is no dramatic change at the percolation concentration, which shows that the interactions are never of infinite range, but involve finite-size clusters [30]. Thus, to date there is no evidence from microscopic probes such as neutron scattering or SR, for any type of order, either conventional long range order, spin freezing or "spin ice" down to ∼50 mK at zero magnetic field.…”

Correlations, spin dynamics, defects: the highly frustrated kagomé bilayer

“…-p p [31,32] or the spinel ZnCr O 2 4 [33], display spin dynamics down to very low temperature. Anyway, the high spin values and/or the 3D character of the frustrated geometry of these compounds remain far from the ideal Heisenberg Kagomé case we are dealing with.…”

Quantum and thermal spin relaxation in the diluted spin iceDy2−xMxTi2O7Snyder1, Ueland2, Mizel3 et al. 2004Phys. Rev. B7311592View full textAdd to dashboardCite

“…Dilution studies of other geometrically frustrated magnets have lent considerable insight into the nature of the low temperature behavior. [21][22][23][24] For example, SrCr 8−x Ga 4+x O 19 (SCGO), a frustrated antiferromagnet with a layered kagomé structure 25,26 has been studied extensively as a function of the concentration of the Cr ions relative to nonmagnetic Ga. While not possessing the level of disorder traditionally associated with spin glasses, SCGO displays a spin glass transition at low temperatures ͑T f ϳ 5 KӶ⌰ Weiss ϳ 500 K͒, which is associated with the geometrical frustration inherent to the kagomé lattice.…”