Schwinger-boson approach to anisotropy ferrimagnetic chain with bond alternation**Project supported by the National Natural Science Foundation of China (Grant No. 10774035) and the Qianjiang RenCai Program of Zhejiang Province, China (Grant No. 2007R0010).

Abstract

We use the Schwinger-boson approach to study the anisotropy ferrimagnetic spin-(1/2,1) chain with bond alternation. Based on the effect of bond alternation δ, we obtain energy gap, free energy, and specific heat, respectively. The specific heat with larger bond alternation (δ > 0.7) displays a peak at low temperature. Based on the effect of XXZ anisotropy parameter Δ, we present excited spectrums, free energy, and specific heat, respectively.