Surface magnetism in ZnO/Co3O4 mixtures
Surface magnetism in ZnO/Co3O4 mixtures
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DOI：
10.1063/1.3294649
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发表时间：
2009-12
影响因子：
3.2
通讯作者：
M. Garcı̀a;F. Jiménez-Villacorta;A.Quesada;J. Venta;N. Carmona;I. Lorite;J. Llopis;J. F. Fernández
中科院分区：
文献类型：
--
作者：
M. Garcı̀a;F. Jiménez-Villacorta;A.Quesada;J. Venta;N. Carmona;I. Lorite;J. Llopis;J. F. Fernández
我们最近报道的观察室温铁磁性的混合物中的ZnO和Co3O4，尽管这些氧化物的抗磁性和反铁磁性字符，分别。在这里，我们对这种材料的电子结构进行了详细的研究，以解释意想不到的铁磁性。两种氧化物之间的静电相互作用导致Co3O4颗粒分散在ZnO较大颗粒的表面上。因此，在颗粒表面发生还原Co+3→ Co 2+，如通过X射线吸收光谱测量和光学光谱所证明的。这种减少可以解释观察到的铁磁信号内的良好建立的磁性理论的氧化物。
We recently reported the observation of room temperature ferromagnetism in mixtures of ZnO and Co3O4 despite the diamagnetic and antiferromagnetic character of these oxides, respectively. Here, we present a detailed study on the electronic structure of this material in order to account for the unexpected ferromagnetism. Electrostatic interactions between both oxides lead to a dispersion of Co3O4 particles over the surface of ZnO larger ones. As a consequence, the reduction Co+3→Co2+ at the particle surface takes place as evidenced by x-ray absorption spectroscopy measurements and optical spectroscopy. This reduction allows explaining the observed ferromagnetic signal within the well established theories of magnetism in oxides.