https://doi.org/10.1140/epjb/e2004-00043-y
Thermodynamic properties of an alternating-spin (1/2,1) two-leg ladder
1
Laboratory of Condensed Matter Spectroscopy and Opto-Electronic Physics,
Department of Physics, Shanghai Jiao Tong University, 1954 Hua Shan Road,
Shanghai 200030, P.R. China
2
Department of Physics, Suzhou University, Suzhou, 215006, P.R. China
Corresponding author: a rom@wx88.net
Received:
2
April
2003
Revised:
24
October
2003
Published online:
15
March
2004
With the aid of the Schwinger-boson mean-field method, we study the low-lying excitations and thermodynamic properties of a ferrimagnetic Heisenberg two-leg ladder (i.e., a ferrimagnetic double-chain with an antiferromagnetic interaction). The interaction between the two chains plays an important role in producing a low-lying excitation energy gap, affecting the low-lying excited spectrum, and increasing the disorder of the ferrimagnetic double-chain. The excitation spectrum, energy gap, and spin reduction in the ground state are calculated. Thermodynamic quantities such as the short-range spin correlation and short-range order are also obtained at low temperatures. In this gapful system, we observed the exponential behaviors in both the specific heat (CV) and the product of magnetic susceptibility and temperature () at low temperatures. The exponential behavior of the
versus temperature agrees qualitatively with the experimental results in
at low temperatures.
PACS: 75.10.Jm – Quantized spin models / 75.40.Cx – Static properties (order parameter, static susceptibility, heat capacities, critical exponents, etc.) / 75.50.Ee – Antiferromagnetics / 75.50.Gg – Ferrimagnetics
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2004