Slow and static spin correlations in Dy_{2 +x}Ti_{2 −x}O_{7 − δ}

Abstract

The static and dynamic spin correlations in the spin ices Dy(2.3)Ti(1.7)O(6.85) and Dy(2)Ti(2)O(7) have been studied in polarized neutron diffraction and neutron spin echo experiments. The measurements reveal that, below 100 mK, the magnetic scattering broadens and shifts to higher |Q| upon stuffing the pyrochlore lattice with additional Dy(3+) ions. These observations can be related, by means of reverse Monte Carlo simulation, to the modified distribution of near-neighbour distances and an overall more antiferromagnetic character of the near-neighbour couplings. The dynamic measurements show that the spin correlations are slower in the stuffed system. These results will be discussed and compared to the holmium analogues.

New physics in frustrated magnets: Spin ices, monopoles, etc. (Review Article)

“…The quantum relaxation time is enhanced there, i.e., spin-spin correlations are slower in stuffed spin ices. However, stuffed spin ices do not freeze down to the lowest temperatures, and have basically the same entropy as standard spin ices [248,249,250,251,252,253,254,255]. On the other hand, stuffed spin ice based on Dy does not manifest residual entropy, i.e., spin fluctuations persist there down to lowest temperatures [219,256].…”

“…By stuffed spin ice [84] one means the situation, when magnetic rare-earth ions alter chemically non-magnetic Ti sites, for example Ho 3+ "stuffs" Bsites like in Ho 2 (Ti 2−x Ho x )O 7−δ (where δ > 0 implies the balance of oxygen content due to "stuffing") [248,249,250,251,252,253,254,255]. Such a procedure, naturally, introduces randomness to the spin ice, and one would expect enhancement of spin glass-like behavior, e.g., the transition to the ordered spin-glass state.…”

Evidence for unidimensional low-energy excitations as the origin of persistent spin dynamics in geometrically frustrated magnets

“…However this interpretation of the Dy 2 Ti 2 O 7 data 35,36 leads to a muon hopping rate nearly three orders of magnitude larger than that measured on the isostructural non-magnetic material Y 2 Ti 2 O 7 . 37 Moreover spin dynamics has been detected in Dy 2 Ti 2 O 7 down to 0.1 K. 38 Although no data is available concerning muon diffusion in CdHo 2 S 4 , here we will not consider this possibility. Indeed, the similarity of the data in this material, in the pyrochlore systems listed at the beginning of this text, and in Cu 2 Cl(OH) 3 strongly suggests that an explanation generic to three dimensional networks of corner sharing tetrahedral spins must pertain.…”

Self-We-Others Schemata Differentiation as a Base for Personal Agency and Social Attitudes

“…We hypothesized that some people have some insight into implicit information. To test this hypothesis, we used the implicit semantic priming paradigm: the subliminal exposition of words (Dobrenko and Jarymowicz, 2011 ). The participants were told that some words were invisible, and then subsequently asked to indicate which of the set of two explicitly exposed words—a synonym or a new word—corresponded to the word presented subliminally.…”