Eur. Phys. J. B 49, 403-406 (2006)
https://doi.org/10.1140/epjb/e2006-00088-x

Softening of spin-wave stiffness near the ferromagnetic phase transition in diluted magnetic semiconductors

¹ Department of Applied Physics, National University of Kaohsiung, Kaohsiung, 811, Taiwan, ROC
² Department of Physics, National Tsing-Hua University, Hsinchu 300, National Center for Theoretical Science, Hsinchu, 300, Taiwan

Corresponding author: ^a sjs@nuk.edu.tw

Received: 1 November 2005
Published online: 31 March 2006

Abstract

Employing the self-consistent Green's function approach, we studied the temperature dependence of the spin-wave stiffness in diluted magnetic semiconductors. Note that the Green's function approach includes the spatial and temperature fluctuations simultaneously which was not possible within conventional Weiss mean-field theory. It is rather interesting that we found the stiffness becomes dramatically softened as the critical temperature is approached, which seems to explain the mysterious sharp drop of magnetization curves in samples within diffusive regime.