Influence of processing conditions on the crystal structure and magnetic behavior of La0.7Ca0.3MnO3±δ samples

被引：23

作者：

Lisboa, PN

Mombrú, AW

Pardo, H

Ortiz, WA

Leite, ER

机构：

[1] Univ Fed Sao Carlos, Lab Interdisciplinar Eletroquim & Ceram, Dept Quim, CMDMC, BR-13565905 Sao Carlos, SP, Brazil

[2] Univ Fed Sao Carlos, Grp Supercondut & Magnetismo, Dept Fis, CMDMC, BR-13565905 Sao Carlos, SP, Brazil

[3] Univ Republica, Lab Cristalog & Quim Estado Solido, DEQUIFIM, Fac Quim, Montevideo, Uruguay

来源：

JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS | 2003年 / 64卷 / 04期

基金：

巴西圣保罗研究基金会;

关键词：

microstructure; COLOSSAL-MAGNETORESISTANCE; OXYGEN STOICHIOMETRY; TRANSPORT-PROPERTIES; INHOMOGENEITY; TEMPERATURE; RESISTIVITY; HOMOGENEITY;

D O I：

10.1016/S0022-3697(02)00353-0

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

In this work we report crystallographic structure variations and the related modifications on the magnetic behavior of La0.7Ca0.3MnO3+/-delta introduced by heat-treatments in different synthesis atmospheric conditions. We have prepared polycrystalline ceramic samples using a modified polymeric precursors method, which produces highly homogeneous specimens. The use of argon atmosphere enlarges the crystalline c-axis as detected by Rietveld refinements. As a consequence, an improvement in the magnetic transition temperature T-C of the samples was observed. Our results also indicate that different heat-treatment conditions change the magnetic interactions between the ferromagnetic (F) and antiferromagnetic (AF) structures of these systems. Our conclusions rely on the use of AC magnetic susceptibility measurements as the experimental tool for measuring these variations. (C) 2003 Elsevier Science Ltd. All rights reserved.

引用

页码：583 / 591

页数：9

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