Dynamic properties of a diluted pyrochlore cooperative paramagnet (Tb_pY_{1-p})_2Ti_2O_7

TL;DR

This study explores the spin dynamics in a geometrically frustrated pyrochlore material, revealing persistent paramagnetic fluctuations at low temperatures influenced by dilution, with implications for understanding cooperative spin behavior.

Contribution

It provides new insights into how dilution affects spin fluctuations and demonstrates that the percolation threshold is not critical for these fluctuations in the studied pyrochlore.

Findings

Paramagnetic fluctuations persist as temperature approaches zero for all dilution levels.

Dilution slows down the spin fluctuations and affects the spectral density.

The spectral density exhibits a 1/f behavior at low temperatures.

Abstract

Investigations of the spin dynamics of the geometrically frustrated pyrochlore (Tb_pY_{1-p})_2Ti_2O_7, 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 temperatures spectral density has a 1/f behavior, and that dilution slows down the spin fluctuations.