Dynamic properties of a diluted pyrochlore cooperative paramagnet (TbpY1-p)2Ti2O7 -: art. no. 107204

Investigations of the spin dynamics of the geometrically frustrated pyrochlore (TbpY1-p)(2)Ti2O7, 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 p(c) 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.