Low-energy excitations and thermodynamical properties of the quantum (5/2, 1/2, 1/2) ferrimagnetic chain

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)2BNOR ] (R = H, F, Cl, Br) with one-dimensional chain structure.

Low-energy structure of the homometallic intertwining double-chain ferrimagnetsA3Cu3(PO4)4Yamamoto1, Ohara2 2007Phys. Rev. B186160View full textAdd to dashboardCite

“…A minimum of S͑0͒ as a function of temperature is characteristic of ferrimagnets. 6,7,18,25,30,[52][53][54] S͑0͒ monotonically decreases and increases with increasing temperature in ferromagnets and antiferromagnets, respectively.…”

“…The metal-radical hybrid strategy, combined with fabrication of novel polyradicals, 16 yielded various polymerized heterospin chain compounds. 17,18 Homometallic ferrimagnetism is also realizable 19,20 but its mechanism is often more subtle, essentially depending on the structural features of the system. Coronado et al 21,22 pioneeringly synthesized chain-structured compounds of such kind, M 2 ͑EDTA͒͑H 2 O͒ 4 ·2H 2 O ͑M = Ni, Co; EDTA = ethylenediamminetetraacetate= C 10 N 2 O 8 ͒, whose ferrimagnetic behavior originates from the alternating g factors and is therefore faint.…”

Application of Symmetry Methods to Low-Dimensional Heisenberg Magnets

“…We apply the resulting algorithm to the ferrimagnetic (5/2,1) cluster as shown in Figure4, where the sites with even and odd numbers correspond to spins with S = 1 and S = 5/2, respectively. Monitoring the energy per bond ε g [Equation (30)] and sublattice magnetizations [Equations (32,33)] in the ground state, we increase a size of blocks to reach values comparable with those found by the spin-wave theory (SWT) [60] and the MPM [58,59]. For the system under study, whose correlation length is so small as to be comparable to the unit-cell length, the results are achieved with the 9-site cluster (N = In the calculation, the ground state has the spin S = 5 in agreement with Lieb-Mattis theorem [61], then possible values S u = 4, 5, and 6.…”

“…Below, we consider the enhanced MCE in the example of the (5/2, 1) ferrimagnetic model considered previously in the study of molecule-based heterospin magnets [Mn(hfac) 2 BNO R ] (R=H, F, Cl, Br) [58,59]. Our goal is to calculate the entropy S at the temperature T and the magnetic field H invoking the formalism of SU (2) group.…”

Algebra Solutions of Antiferromagnet-Antiferromagnet-Ferromagnet Quantum Heisenberg Chains Related to Sp(6,R) Lie Algebra

“…We consider the model of a 1D AF-AF-F spin chain ( 5 2 , 1 2 , 1 2 ) of described by the Hamiltonian [7] …”