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Coupling Between Magnetic Exchange and Charge Activation in Cu‐Doped LaFeO 3
Author(s) -
Dogdibegovic Emir,
Cai Qingsheng,
James William J.,
Yelon William B.,
Anderson Harlan U.,
Yang JinBo,
Zhou XiaoDong
Publication year - 2016
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.14061
Subject(s) - superexchange , neutron diffraction , materials science , antiferromagnetism , thermoelectric effect , doping , perovskite (structure) , condensed matter physics , seebeck coefficient , ferromagnetism , crystallography , chemistry , crystal structure , physics , thermal conductivity , optoelectronics , composite material , thermodynamics
Material research on perovskite‐type oxides (ABO 3 ) has been driven by the recognition of their unique properties primarily attributed to the presence of oxygen octahedron (BO 6 ). Since 2003, the discovery of strong coupling in TbMnO 3 and BiFeO 3 has stimulated new interests in understanding the relationship between magnetic and electric properties in perovskites. In this article, we report our recent work on the magnetic superexchange interaction and charge formation in copper‐doped LaFeO 3 using high‐temperature neutron diffraction and thermoelectric measurements. In situ neutron diffraction measurements show a loss of antiferromagnetic ordering above 450°C. With an increase in Cu content, the (Fe, Cu)‐O bond length decreases and the (Fe, Cu)–O–(Fe, Cu) bond angle increases, which leads to an enhancement of the Fe–O–Fe superexchange interaction. Thermoelectric and electrical measurements show that the formation of electron holes in Cu‐doped LaFeO 3 is a thermally activated process with two distinct regions with a transition temperature near 450°C, in congruence with the magnetic measurements. Our work show that Cu is in 3+ state in La(Fe,Cu)O 3 at room temperature, resulting in the maximum superexchange interaction between Fe 3+ ions.