Phase-pure eutectic CoFe2O4-Ba1-xSrxTiO3 composites prepared by floating zone melting

被引:6
作者
Breitenbach, Martin [1 ]
Ebbinghaus, Stefan G. [1 ]
机构
[1] Martin Luther Univ Halle Wittenberg, Inst Chem, Kurt Mothes Str 2, D-06120 Halle, Germany
关键词
Eutectics; Floating zone technique; Composites; Magnetoelectric materials; Magnetic materials; MAGNETIC-PROPERTIES; MAGNETOELECTRIC BEHAVIOR; NANOPARTICLES; COFE2O4; COMBUSTION; NIFE2O4; OXIDE; SIZE;
D O I
10.1016/j.jcrysgro.2017.11.003
中图分类号
O7 [晶体学];
学科分类号
0702 ; 070205 ; 0703 ; 080501 ;
摘要
Composites consisting of ferrimagnetic CoFe2O4 and ferroelectric Ba1-xSrxTiO3 were grown by the floating zone technique. The influence of Sr substitution, growth rate and atmosphere during the floating zone process were investigated. The formation of the non-ferroelectric, hexagonal modification of BaTiO3 was avoided by a slight Sr substitution of 3 mol% and the formation of BaFe12O19 was suppressed using pure nitrogen as atmosphere during the floating zone melting. These synthesis parameters led to phase-pure, but electrically conductive CoFe2O4-Ba1-xSrxTiO3 composites. A thermal treatment at 973 K in air resulted in a strong increase of the electric resistivity accompanied by a decrease of the unit-cell parameters of both components indicating the healing of oxygen defects. SEM investigations revealed a variety of different geometric structures and crack-free interfaces between both phases. The low porosities observed in the micrographs correspond with densities above 90%. Magnetoelectric (ME) measurements confirmed a coupling between the ferroic orders of both phases with a hysteresis and maximum alpha(ME) of 1.3 mV Oe(-1) cm(-1). (C) 2017 Elsevier B.V. All rights reserved.
引用
收藏
页码:81 / 88
页数:8
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