1. Coupling Between Magnetic Exchange and Charge Activation in Cu‐Doped LaFeO 3
- Author
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William B. Yelon, Jinbo Yang, Qingsheng Cai, William Joseph James, Emir Dogdibegovic, Harlan U. Anderson, and Xiao-Dong Zhou
- Subjects
Materials science ,Condensed matter physics ,Transition temperature ,Neutron diffraction ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Bond length ,Molecular geometry ,Superexchange ,Chemical physics ,0103 physical sciences ,Thermoelectric effect ,Materials Chemistry ,Ceramics and Composites ,Antiferromagnetism ,Electrical measurements ,010306 general physics ,0210 nano-technology - Abstract
Material research on perovskite-type oxides (ABO3) has been driven by the recognition of their unique properties primarily attributed to the presence of oxygen octahedron (BO6). Since 2003, the discovery of strong coupling in TbMnO3 and BiFeO3 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 LaFeO3 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 LaFeO3 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)O3 at room temperature, resulting in the maximum superexchange interaction between Fe3+ ions.
- Published
- 2016