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The European Physical Journal B
ISSN: 1434-6028 (printed version)
ISSN: 1434-6036 (electronic version)
Abstract Volume 3 Issue 3 (1998) pp 333-340
Explanation of the Cu spin-wave excitation gap in Nd$_{\mathsf 2}$CuO$_{\mathsf 4}$
T. Pyttlik (a), K.W. Becker
Institut für Theoretische Physik, Technische Universität Dresden, 01062 Dresden, Germany
Received: 13 August 1997 / Revised: 4 December 1997 / Accepted: 11 December 1997
Abstract: By use of a mean-field approach the spin-wave dispersion of the Cu degrees of freedom in the undoped high-T C material Nd2CuO4is investigated. The experimentally observed sharp decrease of the Cu spin-wave gap with increasing temperature in the range $T^\ast < T < T_{N}$ is explained by a paramagnetic-like susceptibility of the Nd spins which couple to the Cu subsystem. The degeneracy of the "in-plane" and "out-of-plane" polarized Cu spin-wave branches is shown to be lifted by the uniaxial anisotropy of the Cu-Cu nearest-neighbor interaction.
PACS. 74.72.Dn La-based cuprates - 75.30.Cr Saturation moments and magnetic susceptibilities - 75.40.Gb Dynamic properties (dynamic susceptibility, spin waves, spin diffusion, dynamic scalling, etc.)
(a) email: pyttlik@physik.tu-dresden.de
Article in PDF-Format (359 KB)
Online publication: July 14, 1998
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