Reexamination of the microscopic couplings of the quasi one-dimensional antiferromagnet CuGeO_3

Дата и время публикации : 1997-05-05T15:05:43Z

Авторы публикации и институты :
K. Fabricius
A. Klümper
U. Löw
B. Büchner
T. Lorenz

Ссылка на журнал-издание: Ссылка на журнал-издание не найдена
Коментарии к cтатье: 9 pages, REVTEX, 5 figures
Первичная категория: cond-mat.str-el

Все категории : cond-mat.str-el

Краткий обзор статьи: Experimental data for the magnetic susceptibility and magnetostriction of CuGeO_3 are analyzed within a one-dimensional antiferromagnetic model with nearest ({J_1}) and next-nearest neighbour interactions ({J_2}). We show that the ratio of the exchange constants in the antiferromagnetic chains of CuGeO_3 amounts to ${J_2}/{J_1}$ = 0.354(0.01), i.e. it is significantly larger than the critical value for the formation of a spontaneous gap in the magnetic excitation spectrum without lattice dimerization. The susceptibility data are reproduced by our numerical results over the temperature range from 20K to 950K to a high degree of accuracy for ${J_1} = 80.2 (3.0)$ and ${J_2} = 28.4 (1.8)$. The pressure dependence of the exchange constants is estimated from magnetostriction data. Furthermore, the specific heat data are checked on consistency against the calculated entropy of the above model.

Category: Physics