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Title: Exchange bias effect in Au-Fe3O4 dumbbell nanoparticles induced by the charge transfer from gold

Abstract

We have studied the origin of the exchange bias effect in the Au-Fe3O4 dumbbell nanoparticles in two samples with different sizes of the Au seed nanoparticles (4.1 and 2.7 nm) and same size of Fe3O4 nanoparticles (9.8 nm). The magnetization, small-angle neutron-scattering, synchrotron x-ray diffraction, and scanning transmission electron microscope measurements determined the antiferromagnetic FeO wustite phase within Fe3O4 nanoparticles, originating at the interface with the Au nanoparticles. The interface between antiferromagnetic FeO and ferrimagnetic Fe3O4 is giving rise to the exchange bias effect. The strength of the exchange bias fields depends on the interfacial area and lattice mismatch between both phases. We propose that the charge transfer from the Au nanoparticles is responsible for a partial reduction of the Fe3O4 into the FeO phase at the interface with Au nanoparticles. The Au-O bonds are formed, presumably across the interface to accommodate an excess of oxygen released during the reduction of magnetite

Authors:
; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science - Office of Basic Energy Sciences - Materials Sciences and Engineering Division; USDOE Office of Science - Office of Biological and Environmental Research; USDOE Office of Science - Office of Basic Energy Sciences - Scientific User Facilities Division
OSTI Identifier:
1240279
DOE Contract Number:  
AC02-06CH11357
Resource Type:
Journal Article
Journal Name:
Physical Review. B, Condensed Matter and Materials Physics
Additional Journal Information:
Journal Volume: 92; Journal Issue: 5; Journal ID: ISSN 1098-0121
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English

Citation Formats

Feygenson, Mikhail, Bauer, John C., Gai, Zheng, Marques, Carlos, Aronson, Meigan C., Teng, Xiaowei, Su, Dong, Stanic, Vesna, Urban, Volker S., Beyer, Kevin A., and Dai, Sheng. Exchange bias effect in Au-Fe3O4 dumbbell nanoparticles induced by the charge transfer from gold. United States: N. p., 2015. Web. doi:10.1103/PhysRevB.92.054416.
Feygenson, Mikhail, Bauer, John C., Gai, Zheng, Marques, Carlos, Aronson, Meigan C., Teng, Xiaowei, Su, Dong, Stanic, Vesna, Urban, Volker S., Beyer, Kevin A., & Dai, Sheng. Exchange bias effect in Au-Fe3O4 dumbbell nanoparticles induced by the charge transfer from gold. United States. doi:10.1103/PhysRevB.92.054416.
Feygenson, Mikhail, Bauer, John C., Gai, Zheng, Marques, Carlos, Aronson, Meigan C., Teng, Xiaowei, Su, Dong, Stanic, Vesna, Urban, Volker S., Beyer, Kevin A., and Dai, Sheng. Mon . "Exchange bias effect in Au-Fe3O4 dumbbell nanoparticles induced by the charge transfer from gold". United States. doi:10.1103/PhysRevB.92.054416.
@article{osti_1240279,
title = {Exchange bias effect in Au-Fe3O4 dumbbell nanoparticles induced by the charge transfer from gold},
author = {Feygenson, Mikhail and Bauer, John C. and Gai, Zheng and Marques, Carlos and Aronson, Meigan C. and Teng, Xiaowei and Su, Dong and Stanic, Vesna and Urban, Volker S. and Beyer, Kevin A. and Dai, Sheng},
abstractNote = {We have studied the origin of the exchange bias effect in the Au-Fe3O4 dumbbell nanoparticles in two samples with different sizes of the Au seed nanoparticles (4.1 and 2.7 nm) and same size of Fe3O4 nanoparticles (9.8 nm). The magnetization, small-angle neutron-scattering, synchrotron x-ray diffraction, and scanning transmission electron microscope measurements determined the antiferromagnetic FeO wustite phase within Fe3O4 nanoparticles, originating at the interface with the Au nanoparticles. The interface between antiferromagnetic FeO and ferrimagnetic Fe3O4 is giving rise to the exchange bias effect. The strength of the exchange bias fields depends on the interfacial area and lattice mismatch between both phases. We propose that the charge transfer from the Au nanoparticles is responsible for a partial reduction of the Fe3O4 into the FeO phase at the interface with Au nanoparticles. The Au-O bonds are formed, presumably across the interface to accommodate an excess of oxygen released during the reduction of magnetite},
doi = {10.1103/PhysRevB.92.054416},
journal = {Physical Review. B, Condensed Matter and Materials Physics},
issn = {1098-0121},
number = 5,
volume = 92,
place = {United States},
year = {2015},
month = {8}
}