Lattice dynamical study of optical modes in Tl2Mn2O7 and In2Mn2O7 pyrochlores -: art. no. 054434

被引：41

作者：

Brown, S

Gupta, HC ^{[1
]}

Alonso, JA

Martínez-Lope, MJ

机构：

[1] Indian Inst Technol, Dept Phys, New Delhi 110016, India

[2] CSIC, Inst Ciencia Mat Madrid, E-28049 Madrid, Spain

来源：

PHYSICAL REVIEW B | 2004年 / 69卷 / 05期

关键词：

D O I：

10.1103/PhysRevB.69.054434

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

The Raman and IR spectra and force field have been investigated for A(2)Mn(2)O(7) (A=Tl,In) by means of a short-range force constant model which includes four stretching and four bending force constants. Unusual spectral and force field changes are observed and analyzed. The stretching force constant Mn-O and A-O-' are found to be relatively higher than those of other pyrochlore oxides of the A(2)Mn(2)O(7) family, while the remaining force constant values are significantly smaller, especially for Tl2Mn2O7. This trend may be due to strong hybridization of the Tl (6s) orbital with O (2p) and Mn (3d). The assignment of all the modes has been proposed and potential energy distribution is also reported. The evaluated frequencies are close to the available observed infrared and Raman frequencies, giving further support to the present assignments.

引用

页数：6

共 23 条

[1] Unprecedented magnetoresistance in Cd-substituted Tl2Mn2O7 pyrochlores [J].