skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

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];  [2]
  1. National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, Anhui (China)
  2. (China)
Publication Date:
OSTI Identifier:
22590818
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 108; Journal Issue: 25; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
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, E-mail: ywsh2000@ustc.edu.cn, E-mail: zhsun@ustc.edu.cn, Yan, Wensheng, E-mail: ywsh2000@ustc.edu.cn, E-mail: zhsun@ustc.edu.cn, 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, E-mail: ywsh2000@ustc.edu.cn, E-mail: zhsun@ustc.edu.cn, Yan, Wensheng, E-mail: ywsh2000@ustc.edu.cn, E-mail: zhsun@ustc.edu.cn, 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, E-mail: ywsh2000@ustc.edu.cn, E-mail: zhsun@ustc.edu.cn, Yan, Wensheng, E-mail: ywsh2000@ustc.edu.cn, E-mail: zhsun@ustc.edu.cn, 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, E-mail: ywsh2000@ustc.edu.cn, E-mail: zhsun@ustc.edu.cn and Yan, Wensheng, E-mail: ywsh2000@ustc.edu.cn, E-mail: zhsun@ustc.edu.cn 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},
number = 25,
volume = 108,
place = {United States},
year = {Mon Jun 20 00:00:00 EDT 2016},
month = {Mon Jun 20 00:00:00 EDT 2016}
}