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Title: Intrinsic ferromagnetic coupling in Co{sub 3}O{sub 4} quantum dots activatedby graphene hybridization

Abstract

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 Co{sub 3}O{sub 4}, by virtue of a hybrid structure that modifies the valence state of Co ions. The Co{sub 3}O{sub 4} quantum dots exhibit ferromagnetism of 2.2 emu/g at 2 K after hybridization with reduced graphene oxide (RGO). In this hybrid structure, electron-transfer from RGO to Co{sub 3}O{sub 4} occurs and Co{sup 3+} ions occupying the octahedral (O{sub h}) positions are converted into Co{sup 2+}. Then the super-exchange interactions between Co{sup 2+} ions at T{sub d} (tetrahedral) and O{sub h} positions switch the magnetic coupling of Co{sup 2+}(T{sub d})–Co{sup 2+}(T{sub d}) from antiferromagnetic to ferromagnetic. These results offer promise for tailoring the spin exchange interactions of oxide semiconductors for spintronics applications.

Authors:
; ; ; ; ; ;  [1]; ; ;  [1]
  1. National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, Anhui (China)
Publication Date:
OSTI Identifier:
22590818
Resource Type:
Journal Article
Journal Name:
Applied Physics Letters
Additional Journal Information:
Journal Volume: 108; Journal Issue: 25; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0003-6951
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ANTIFERROMAGNETISM; COBALT IONS; COBALT OXIDES; COUPLINGS; EXCHANGE INTERACTIONS; GRAPHENE; METALS; QUANTUM DOTS; SEMICONDUCTOR MATERIALS; SPIN EXCHANGE; VALENCE

Citation Formats

Chen, Lin, Hu, Fengchun, Duan, Hengli, Liu, Qinghua, Tan, Hao, Yao, Tao, Sun, Zhihu, Yan, Wensheng, Jiang, Yong, Wei, Shiqiang, and Hefei Science Center, Chinese Academy of Sciences, Hefei 230029. Intrinsic ferromagnetic coupling in Co{sub 3}O{sub 4} quantum dots activatedby graphene hybridization. United States: N. p., 2016. Web. doi:10.1063/1.4954715.
Chen, Lin, Hu, Fengchun, Duan, Hengli, Liu, Qinghua, Tan, Hao, Yao, Tao, Sun, Zhihu, Yan, Wensheng, Jiang, Yong, Wei, Shiqiang, & Hefei Science Center, Chinese Academy of Sciences, Hefei 230029. Intrinsic ferromagnetic coupling in Co{sub 3}O{sub 4} quantum dots activatedby graphene hybridization. United States. doi:10.1063/1.4954715.
Chen, Lin, Hu, Fengchun, Duan, Hengli, Liu, Qinghua, Tan, Hao, Yao, Tao, Sun, Zhihu, Yan, Wensheng, Jiang, Yong, Wei, Shiqiang, and Hefei Science Center, Chinese Academy of Sciences, Hefei 230029. Mon . "Intrinsic ferromagnetic coupling in Co{sub 3}O{sub 4} quantum dots activatedby graphene hybridization". United States. doi:10.1063/1.4954715.
@article{osti_22590818,
title = {Intrinsic ferromagnetic coupling in Co{sub 3}O{sub 4} quantum dots activatedby graphene hybridization},
author = {Chen, Lin and Hu, Fengchun and Duan, Hengli and Liu, Qinghua and Tan, Hao and Yao, Tao and Sun, Zhihu and Yan, Wensheng and Jiang, Yong and Wei, Shiqiang and Hefei Science Center, Chinese Academy of Sciences, Hefei 230029},
abstractNote = {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 Co{sub 3}O{sub 4}, by virtue of a hybrid structure that modifies the valence state of Co ions. The Co{sub 3}O{sub 4} quantum dots exhibit ferromagnetism of 2.2 emu/g at 2 K after hybridization with reduced graphene oxide (RGO). In this hybrid structure, electron-transfer from RGO to Co{sub 3}O{sub 4} occurs and Co{sup 3+} ions occupying the octahedral (O{sub h}) positions are converted into Co{sup 2+}. Then the super-exchange interactions between Co{sup 2+} ions at T{sub d} (tetrahedral) and O{sub h} positions switch the magnetic coupling of Co{sup 2+}(T{sub d})–Co{sup 2+}(T{sub d}) from antiferromagnetic to ferromagnetic. These results offer promise for tailoring the spin exchange interactions of oxide semiconductors for spintronics applications.},
doi = {10.1063/1.4954715},
journal = {Applied Physics Letters},
issn = {0003-6951},
number = 25,
volume = 108,
place = {United States},
year = {2016},
month = {6}
}