Посилання:Specific heat study of magnetic excitations in a one-dimensional S =1 Heisenberg magnet with strong planar anisotropy / A.Feher, M.Orendáč, A.Orendáčová, E.Čižmár // Физика низких температур. — 2002. — Т. 28, № 7. — С. 768-773. — Бібліогр.: 12 назв. — англ.
Підтримка:We are grateful to Prof. V. V. Eremenko for introducing
our Košice group to the wonderful world
of low-dimensional magnetism many years ago.
One of us (A. F.) acknowledges the hospitality of
CRTBT CNRS Grenoble during the preparation of
this manuscript. Partial financial support for this
work was provided by the grant No. 1/7473/20
from the Slovak Ministry of Education. The material
support of U. S. Steel DZ Energetika is gratefully
acknowledged.
The results of experimental studies of the specific heat of the magnetic chain compounds Ni(C₂H₈N₂)₂Ni(CN)₄, Ni(C₁₁H₁₀N₂O)₂Ni(CN)₄, and Ni(C₁₀H₈N₂)₂Ni(CN)₄⋅H₂O are reported. All compounds are identified as S=1 planar Heisenberg magnetic chains with large planar anisotropy and different values of the in-plane anisotropy constant. The low-temperature specific heat data are interpreted assuming the existence of noninteracting excitons and antiexcitons as elementary excitations from the singlet-ground state. The extended strong-coupling model is used for analysis of the data at higher temperatures. The applicability of the models used with respect to the value of the in-plane anisotropy is discussed.