Low Temperature Physics: 28, 551 (2002); https://doi.org/10.1063/1.1496666 (5 pages)
Физика Низких Температур: Том 28, Выпуск 7 (Июль 2002), c. 768-773    ( к оглавлению , назад )

Specific heat study of magnetic excitations in a one-dimensional S =1 Heisenberg magnet with strong planar anisotropy

A. Feher, M. Orendáč, A. Orendáčová, and E. Čižmár

Department of Experimental Physics, Faculty of Science, P.J.Šafárik University, Park Angelinum 9, 04154 Košice, Slovakia
E-mail: feher@kosice.upjs.sk

Received February 14, 2002

Аннотация

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.

PACS:
75.40.Cx - Static properties (order parameter, static susceptibility, heat capacities, critical exponents, etc.)
71.20.Be - Transition metals and alloys
75.50.Ee - Antiferromagnetics