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We have measured the static and dynamic spin fluctuations in a crystal of La2-v Sr v Cu04+ > in the spin-glass doping regime. The static spin correlations are well described by a simple model in which the inverse correlation length K(X,T) = S K(X,0) +K(0,T).The dynamic spin fluctuations exhibit a simple scaling behavior in co/T for temperatures 10 K4+ v series that the spin fluctuations at low energies (say co -6 meV, using ft=A:# = l as we will throughout) have comparable strengths in antiferromagnetic, spinglass, and superconducting samples [4].In this paper we report on a detailed study of the instantaneous and dynamic spin fluctuations for a crystal of Lai.96Sro.o4Cu04 which is in the intermediate spin-glass regime. These measurements are part of a more global study of the nature of the crossover from antiferromagnetic to spin-glass behavior which will be reported at a later date [5]. However, our results for the dynamics are sufficiently novel and, in our view, important that we wish to report those results separately here. We find that the instantaneous correlations are well described by a simple model in which tc(x,T) -K(X,0) + K(0,T) [5,6]. The spin-spin correlation length, ^ = K: _1 (JC,0), is -40 A and K(X,T) is temperature independent below 300 K. Studies of the dynamics in the CuC>2 plane reveal that the fluctuations are centered about the (K^JT) position (square lattice, unit lattice constant notation) with negligible weight at other high-symmetry positions such as (/r,0) and (2/r,0). Our essential new result is that we find that the integrated response around (K,K) as a function of temperature T exhibits a simple scaling behavior in co/T for temperatures 10 K;S7':<500 K and energies 4.5 meV< co< 12 meV. This scaling leads to a natural explanation of a variety of normal-state properties of the copper oxides.Before discussing the experiments, we note that the transport in our La2-v Sr Y Cu04+ > single crystals has been extensively investigated by Preyer et al. [7]. In the doping regime 0.02

We have measured the sublattice magnetization of stoichiornetric La2Cu04 (T&=325 K) and La&Cuo 95zn0 0504 (T~157 K). We discuss the data for La&Cu04 and other lamellar copper oxides in terms of the quantum Heisenberg model including weak XY anisotropy and interlayer coupling. Spinwave theory and a generalized Schwinger-boson mean-field theory are used to predict the ordered rnoment as a function of temperature without adjustable parameters. We also discuss the inhuence of different dopants on the Neel temperature and sublattice magnetization.

We report the results of a direct search for the 229 Th (I p = 3/2 + ← 5/2 + ) nuclear isomeric transition, performed by exposing 229 Th-doped LiSrAlF6 crystals to tunable vacuum-ultraviolet synchrotron radiation and observing any resulting fluorescence. We also use existing nuclear physics data to establish a range of possible transition strengths for the isomeric transition. We find no evidence for the thorium nuclear transition between 7.3 eV and 8.8 eV with transition lifetime (1-2) s τ (2000-5600) s. This measurement excludes roughly half of the favored transition search area and can be used to direct future searches.

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