Intrinsic ferromagnetic coupling in Co3O4 quantum dots activated by graphene hybridization
Intrinsic ferromagnetic coupling in Co3O4 quantum dots activated by graphene hybridization
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石墨烯杂化激活 Co3O4 量子点的本征铁磁耦合
DOI：
10.1063/1.4954715
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发表时间：
2016-06-20
影响因子：
4
通讯作者：
Wei, Shiqiang
中科院分区：
文献类型：
--
作者：
Chen, Lin;Hu, Fengchun;Wei, Shiqiang
在反铁磁金属氧化物半导体中激活过渡金属离子的铁磁耦合对于产生用于自旋电子学应用的铁磁半导体是期望的。在这里，我们报告的内在铁磁耦合在一个典型的反铁磁金属氧化物Co 3 O 4，凭借的混合结构，修改Co离子的价态。Co 3 O 4量子点与还原氧化石墨烯（RGO）杂化后，在2K下具有2.2emu/g的铁磁性。在这种混合结构中，发生从RGO到Co 3 O 4的电子转移，并且占据八面体（O-h）位置的Co 3+离子被转化为Co2+。然后，四面体和O-h位置的Co ~（2+）离子之间的超交换作用使Co ~（2+）（T-d）-Co ~（2+）（T-d）的磁耦合由反铁磁转变为铁磁。这些结果提供了定制的自旋电子学应用的氧化物半导体的自旋交换相互作用的承诺。出版社：AIP Publishing
Activating ferromagnetic couplings of transition-metallic ions in the antiferromagnetic metal oxide semiconductors is desired for creating ferromagnetic semiconductors for spintronics applications. Here, we report intrinsic ferromagnetic coupling in a typical antiferromagnetic metal oxide Co3O4, by virtue of a hybrid structure that modifies the valence state of Co ions. The Co3O4 quantum dots exhibit ferromagnetism of 2.2 emu/g at 2K after hybridization with reduced graphene oxide (RGO). In this hybrid structure, electron-transfer from RGO to Co3O4 occurs and Co3+ ions occupying the octahedral (O-h) positions are converted into Co2+. Then the super-exchange interactions between Co2+ ions at T-d (tetrahedral) and O-h positions switch the magnetic coupling of Co2+(T-d)-Co2+(T-d) from antiferromagnetic to ferromagnetic. These results offer promise for tailoring the spin exchange interactions of oxide semiconductors for spintronics applications. Published by AIP Publishing.