Structural and magnetotransport properties of the colossal magnetoresistance material Tl2Mn2O7

被引：50

作者：

Shimakawa, Y ^{[1
]}

Kubo, Y ^{[1
]}

Manako, T ^{[1
]}

Sushko, YV ^{[1
]}

Argyriou, DN ^{[1
]}

Jorgensen, JD ^{[1
]}

机构：

[1] ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439

来源：

PHYSICAL REVIEW B | 1997年 / 55卷 / 10期

关键词：

D O I：

10.1103/PhysRevB.55.6399

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

The crystal structure and its variation with temperature of the spin-charge coupled material Tl2Mn2O7 pyrochlore is investigated. Structure refinement from the neutron powder-diffraction data reveals that Tl2Mn2O7 has nearly stoichiometric composition and is crystallized in the cubic-pyrochlore-type structure with a characteristic Mn-O-Mn bond angle of 133 degrees. There is no structural anomaly associated with the change in magnetotransport properties at 142 K, suggesting weak spin-lattice and charge-lattice correlations. Despite the similarity of magnetotransport properties observed in the perovskite and the pyrochlore colossal magnetoresistance manganese oxides, the double-exchange mechanism, which is usually applied to the perovskite materials, does not seem to explain the behavior in the pyrochlore Tl2Mn2O7 compound. A superexchange-type interaction may stabilize the ferromagnetic ordering of Mn spins and cause the metallic conduction at low temperatures in Tl2Mn2O7.

引用

页码：6399 / 6404

页数：6

共 28 条

[1]

[Anonymous], 1993, RIETVELD METHOD

[2] Lattice effects and magnetic order in the canted ferromagnetic insulator La(0.87)5Sr(0.125)MnO(3+delta) [J].