Vibrational spectra and force field calculation of A2Mn2O7 (A = Y, Dy, Er, Yb) pyrochlores

被引：56

作者：

Brown, S

Gupta, HC ^{[1
]}

Alonso, JA

Martinez-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：

JOURNAL OF RAMAN SPECTROSCOPY | 2003年 / 34卷 / 03期

关键词：

force field calculations; pyrochlores; lattice dynamic analysis; short-range force model; colossal magnetoresistance;

D O I：

10.1002/jrs.982

中图分类号：

O433 [光谱学];

学科分类号：

0703 ; 070302 ;

摘要：

Raman and infrared spectra were recorded for A(2)Mn(2)O(7) (A = Y, Dy, Er, Yb) pyrochlores. For the first time, lattice dynamic analysis of cubic manganate pyrochlores was carried out using a short-range force model with four stretching and four bending force constants at the zone center. The assignment of all their modes is proposed. The calculated force constants are discussed and compared for the different pyrochlores. The evaluated wavenumbers are close to the available observed infrared and Raman wavenumbers, giving further support to the present assignments. Copyright (C) 2003 John Wiley Sons, Ltd.

引用

页码：240 / 243

页数：4

共 19 条

[1] Enhancement of ferromagnetic coupling in Sb-substituted Tl2Mn2O7 pyrochlores [J].

Alonso, JA ;

Martínez-Lope, MJ ;

Casais, MT ;

Velasco, P ;

Martínez, JL ;

Fernández-Díaz, MT ;

de Paoli, JM .

PHYSICAL REVIEW B, 1999, 60 (22) :R15024-R15027

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

Alonso, JA ;

Velasco, P ;

Martínez-Lope, MJ ;

Casais, MT ;

Martínez, JL ;

Fernández-Díaz, MT ;

de Paoli, JM .

APPLIED PHYSICS LETTERS, 2000, 76 (22) :3274-3276

[3]

BHAGAVANTAM S, 1939, P IND AC SCI A, P224

[4]

Glerup M, 2001, J SOLID STATE CHEM, V160, P25, DOI [10.1006/jssc.2000.9142, 10.1006/jssc.2001.9142]

[5] Phonon raman scattering in A2Mn2O7 (A=Tl,In,Y) [J].

Granado, E ;

Pagliuso, PG ;

Sanjurjo, JA ;

Rettori, C ;

Subramanian, MA ;

Cheong, SW ;

Oseroff, SB .

PHYSICAL REVIEW B, 1999, 60 (09) :6513-6516

[6] A lattice dynamical investigation of the Raman and the infrared frequencies of the cubic A2Hf2O7 pyrochlores [J].

Gupta, HC ;

Brown, S ;

Rani, N ;

Gohel, VB .

JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS, 2002, 63 (03) :535-538

[7] A lattice dynamical investigation of the Raman and the infrared frequencies of the cubic A2Sn2O7 pyrochlores [J].

Gupta, HC ;

Brown, S ;

Rani, N ;

Gohel, VB .

INTERNATIONAL JOURNAL OF INORGANIC MATERIALS, 2001, 3 (07) :983-986

[8]

Gupta HC, 2001, J RAMAN SPECTROSC, V32, P41, DOI 10.1002/1097-4555(200101)32:1<41::AID-JRS664>3.0.CO

[9]

2-R

[10]

Massa NE, 2000, PHYS STATUS SOLIDI B, V220, P373, DOI 10.1002/1521-3951(200007)220:1<373::AID-PSSB373>3.0.CO

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