Specific heat and magnetic susceptibility of ferromagnetic mixed-spin chain systems

Using a combination of high-temperature series expansion, exact diagonalization and Quantum-Monte-Carlo, we perform a complementary analysis of the thermodynamic properties of one-dimensional mixed-spin systems with alternating magnetic moments. In particular, we focus on the difference between ferromagnetic (FM) and antiferromagnetic (AFM) exchange. For the specific heat we find a multi-peak structure in the FM case which is strongly enhanced as compared to that known for the AFM case. We also report the behavior of the susceptibility in the corresponding temperature range. (c) 2005 Elsevier B.V. All rights reserved.