Journal of Physics Condensed Matter
Low-energy excitations and thermodynamical properties of the quantum (5/2, 1/2, 1/2) ferrimagnetic chain
Alexander S. Ovchinnikov, Irina Gennad'evna Bostrem, Vl. E. Sinitsyn, A. S. Boyarchenkov, Н. В. Баранов, Katsuya Inoue
Abstract
The low-energy structures of the quantum ferrimagnetic Heisenberg chain consisting of (5/2, 1/2, 1/2) trimers are investigated theoretically. The results of the linear spin-wave theory are compared with those from the numerical exact diagonalization calculation and the matrix product method for the lowest optical mode. The temperature behaviour of thermodynamical properties such as magnetic susceptibility, specific heat and entropy are analysed in the framework of the modified spin-wave theory. The results of the calculations are used to explain the experimental data obtained for the molecule-based heterospin magnets [Mn(hfac) 2 BNO R ] (R = H, F, Cl, Br) with one-dimensional chain structure.