METAL-INSULATOR TRANSITIONS IN ANION-EXCESS LAMNO3+DELTA CONTROLLED BY THE MN4+ CONTENT

被引:106
作者
VERELST, M
RANGAVITTAL, N
RAO, CNR
ROUSSET, A
机构
[1] INDIAN INST SCI,SOLID STATE & STRUCT CHEM UNIT,BANGALORE 560012,KARNATAKA,INDIA
[2] INDIAN INST SCI,JAWAHARLAL NEHRU CTR ADV SCI RES,BANGALORE 560012,KARNATAKA,INDIA
[3] UNIV TOULOUSE 3,CNRS,URA 1311,CHIM MAT INORGAN LAB,F-31062 TOULOUSE,FRANCE
关键词
D O I
10.1006/jssc.1993.1142
中图分类号
O61 [无机化学];
学科分类号
070301 ; 081704 ;
摘要
LaMnO3+δ samples with Mn4+ content up to 50% have been prepared by different methods. The structure of LaMnO3+δ changes from orthorhombic to cubic (via rhombohedral) with increase in the Mn4+ content. LaMnO3+δ samples containing greater than 20% Mn4+ are ferromagnetic and show resistivity maxima at a temperature Tt which is close to the ferromagnetic Curie temperature. The resistivity maximum is due to the occurrence of a metal-insulator transition. In samples heated to the same temperature, the value of Tt increases with % Mn4+. For a given sample, Tt increases with the temperature of heat treatment due to the increase in particle size. The onset of ferromagnetism in LaMnO3+δ accompanied by an insulator-metal transition is similar to that found in La1-xCaxMnO3 and La1-xSrxCoO3. © 1993 Academic Press, Inc.
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页码:74 / 80
页数:7
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