Вид документа : Статья из журнала Шифр издания : 54/P 36 Автор(ы) : Kellerman D. G., Zhuravlev N. A., Verkhovskii S. V., Medvedev E. Yu., Korolev A. V., Medvedeva J. E. Заглавие : Peculiarities of antiferromagnetic ordering in orthorhombic LiMnO2 Место публикации : Physics of the Solid State. - 2008. - Vol. 50, № 7. - С. 1294-1302 Примечания : Библиогр. : с. 1301 (20 назв.) ББК : 54 Предметные рубрики: ХИМИЧЕСКИЕ НАУКИ Ключевые слова (''Своб.индексиров.''): антиферромагнетики--магнитная восприимчивость--манганит лития Аннотация: Data on the antiferromagnetic ordering in orthorhombic lithium manganite LiMnO2 are obtained from magnetic-susceptibility, calorimetry, and nuclear magnetic resonance studies. The minimal hysteresis and the absence of jumps in the temperature dependences of the sublattice magnetization M(T) and the magnetic susceptibility near TN indicate that the ordering occurs through a continuous second-order phase transition. Within the critical temperature range, the M(T–TN) variation is satisfactorily described by a power-law dependence with a critical exponent β= 0.25(4), which is substantially smaller than that predicted for 3D magnetic systems with isotropic Heisenberg exchange. The band structure of orthorhombic LiMnO2 is calculated using the LMTO–ASA method. Taking into account the spin states of manganese ions, an adequate pattern is obtained for the density-of-states distribution with an energy gap near the Fermi level (~0.7 eV), which is in agreement with the measured electrical parameters of lithium manganite. The calculations demonstrate that the exchange interactions between Mn3+ ions leading to antiferromagnetic ordering are significantly anisotropic. It is found that small paramagnetic regions persist in the manganite below the Néel temperature, and it is concluded that the reason for this is partial structural disordering of LiMnO 2 . As a result, a certain fraction of the manganese positions is occupied by lithium ions (Li Mn ) and vise versa (Mn Li ). These defects are not involved in the formation of the ordered magnetic structure and compose a paramagnetic fraction Держатели документа: Центральная научная библиотека УрО РАН Доп.точки доступа: Kellerman, D. G.; Келлерман Дина Георгиевна; Zhuravlev, N. A.; Журавлев Николай Алексеевич; Verkhovskii, S. V.; Medvedev, E. Yu.; Korolev, A. V.; Medvedeva, J. E.