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Unconventional features of the low‐temperature properties of a dimerized quantum mixed‐spin chain
Author(s) -
SolanoCarrillo E.,
Franco R.,
SilvaValencia J.
Publication year - 2011
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201046183
Subject(s) - antiferromagnetism , condensed matter physics , ferrimagnetism , density matrix renormalization group , ferromagnetism , ground state , spin (aerodynamics) , quantum , chemistry , physics , magnetic field , quantum mechanics , magnetization , thermodynamics
We study the low‐temperature properties of a mixed $(S,s) = (3/2,1/2)$ alternating quantum spin chain with antiferromagnetic–ferromagnetic bond alternation and single‐ion anisotropy using spin‐wave theory, density‐matrix renormalization group calculations and exact diagonalization of finite clusters. An instance in this system is the recently synthesized bimetallic chain $^{1} _{\infty } $ [LCu II Co II (NCS) 2 ], which shows a novel magnetic behavior, namely, the ${\chi} _{M} T$ versus $T$ curve decreases rapidly at low temperatures after displaying a pseudo‐plateau around a certain intermediate temperature. There are two different mechanisms which could explain this unconventional feature: the zero‐field splitting of the ground state and/or the ferromagnetic nature of the interdimer interactions. We clarify the role of these two kinds of mechanisms in the observed properties of the system by deviating from the otherwise‐expected ferrimagnetic ground state and considering a slight deviation from the decoupled‐dimer limit, namely the description of the system by means of effective spin‐1 ions at each unit cell with residual antiferromagnetic interactions, which is consistent with the antiferromagnetic–ferromagnetic bond alternation.