From incommensurate to dispersive spin-fluctuations: The high-energy inelastic spectrum in superconducting YBa2Cu3O6.5
(2004)
Deviations from linear spin wave theory in the 2D, S = 1/2 Heisenberg antiferromagnet CFTD
Journal of Magnetism and Magnetic Materials 272-276 (2004) 896-897
Abstract:
The spin excitation spectrum in the 2D square lattice Heisenberg antiferromagnet CFTD has been investigated using time-of-flight neutron scattering. The magnon dispersion and intensities have been determined as a function of wavevector Q in the full Brillouin zone. Both quantities are found to deviate significantly from the predictions of linear spin wave theory for wavevectors in the vicinity of Q=(π,0), whereas good agreement is found near Q=(π/2,π/2). © 2004 Published by Elsevier B.V.Field-induced quantum phase transition in the quasi 1D XY-like antiferromagnet Cs2 CoCl4
Journal of Magnetism and Magnetic Materials 272-276 (2004) 920-921
Abstract:
We explore the magnetic excitations as a function of applied field in the quasi 1D s=12 XY-like magnet Cs2CoCl4. A transition from spin-flop antiferromagnetic order to a quantum paramagnet occurs at the critical field BC=2.15 T and fields higher than 2.5 T fully align the spins along the field. In the spin-flop phase gapped scattering continua dominate, identified with the creation of pairs of quantum domain walls. In the saturated phase sharp peaks are observed, as expected for magnons in a ferromagnetically ordered ground state. © 2003 Elsevier B.V. All rights reserved.Ferromagnetic in-plane spin fluctuations in NaxCoO2 observed by neutron inelastic scattering
Physical Review Letters 92 (2004) article 197201 4pp
27aXL-1 S=1/2擬2次元三角格子反強磁性体Cs_2CuBr_4の磁場中相転移(量子スピン系,ランダム系 : 二次元系)(領域3)
(2004) 429