2012/07/21 by A. S. F. Tenório, R. R. Montenegro-Filho, M. D. Coutinho-Filho · 1 citation
Physics and Astronomy · #cond-mat.str-el #cond-mat.stat-mech
paper · pdf · doi:10.1088/0953-8984/23/50/506003
published as Journal of Physics. Condensed Matter 23, 506003 (2011)
arxiv created 2012/07/21 · arxiv updated 2012/07/24
The ground state spin-wave excitations and thermodynamic properties of two types of ferrimagnetic chains are investigated: the alternating spin-1/2 spin-5/2 chain and a similar chain with a spin-1/2 pendant attached to the spin-5/2 site. Results for magnetic susceptibility, magnetization and specific heat are obtained through the finite-temperature Lanczos method with the aim in describing available experimental data, as well as comparison with theoretical results from the semiclassical approximation and the low-temperature susceptibility expansion derived from Takahashi's modified spin-wave theory. In particular, we study in detail the temperature vs. magnetic field phase diagram of the spin-1/2 spin-5/2 chain, in which several low-temperature quantum phases are identified: the Luttinger Liquid phase, the ferrimagnetic plateau and the fully polarized one, and the respective quantum critical points and crossover lines.