Experimental evidence for a glass forming stripe liquid in the magnetic ground state of La1.65Eu0.2Sr0.15CuO4 -: art. no. 012415

We report measurements of the longitudinal (T-139(1)-1) and transverse (T-139(2)-1) decay rates of the magnetization of La-139 nuclei performed in a high quality single crystal of La1.65Eu0.2Sr0.15CuO4. We observe a dramatic slowing of the Cu 3d spins manifested as a sharp increase of both T-139(1)-1 and T-139(2)-1 below 30 K. We find that in this temperature range the fluctuations involve a unique time scale tau which diverges as (T-T-A)(-1.9) with T(A)approximate to5 K. This behavior is distinct from the continuous freezing observed in underdoped La1-xSrxCuO4, which involves a distribution of energy barriers. By contrast, in La1.65Eu0.2Sr0.15CuO4, the freezing below 30 K is intrinsic to its magnetic ground state and the observed power law supports the existence of a glass forming "charge stripe liquid."