Spin Correlations in the Paramagnetic Phase and Ring Exchange inLa2CuO4

Spin correlations in the paramagnetic phase and ring exchange in La2CuO4.

Spin correlations in the paramagnetic phase of La(2)CuO(4) have been studied using polarized neutron scattering, with two important results. First, the temperature dependence of the characteristic energy scale of the fluctuations and the amplitude of the neutron structure factor are shown to be in quantitative agreement with the predictions of the quantum nonlinear sigma model. Second, a compar...

Comment on "spin correlations in the paramagnetic phase and ring exchange in La2CuO4".

Anomalous Spin Dynamics in the Paramagnetic Phase of Spin Glasses

Neutron Spin Echo experiments revealed an anomalous paramagnetic phase above the transition temperature in the insulating E U O . ~ S ~ ~ . ~ S , similarly to previously studied metallic spin glasses. The universal signatures of this phase underline the fundamental r61e spin non-conserving forces (anisotropy) and possibly activated processes play in bringing about the spin glass transition. Pre...

Magnetic Phase Diagram of Spin-1/2 Two-Leg Ladder with Four-Spin Ring Exchange

We study the spin-1/2 two-leg Heisenberg ladder with four-spin ring exchanges under a magnetic field. We introduce an exact duality transformation which is an extension of the spin-chirality duality developed previously and yields a new self-dual surface in the parameter space. We then determine the magnetic phase diagram using the numerical approaches of the density-matrix renormalization-grou...

Spin excitation anisotropy in the paramagnetic tetragonal phase of BaFe2As2

Yu Li,1 Weiyi Wang,1 Yu Song,1 Haoran Man,1 Xingye Lu,2 Frédéric Bourdarot,3 and Pengcheng Dai1,2,* 1Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA 2Center for Advanced Quantum Studies and Department of Physics, Beijing Normal University, Beijing 100875, China 3Univ. Grenoble Alpes. CEA, DRF, INAC, MEM/MDN, F-38000 Grenoble, France (Received 16 May 2017; publish...