TY - JOUR
T1 - Modulating the Structure and Magnetic Properties of ϵ-Fe2O3 Nanoparticles via Electrochemical Li+ Insertion
AU - Yasuhara, Sou
AU - Hamasaki, Yosuke
AU - Katayama, Tsukasa
AU - Ao, Takahiro
AU - Inaguma, Yoshiyuki
AU - Hojo, Hajime
AU - Karppinen, Maarit
AU - Philip, Anish
AU - Yasui, Shintaro
AU - Itoh, Mitsuru
N1 - Funding Information:
This work was partly supported by the JSPS KAKENHI Grants-in-Aid for Challenging Research (Pioneering) (M.I. 17H06240), Challenging Research (Exploratory) (Sh.Y. 18K19126), and Scientific Research (B) (S.Y. 19H02426); by the MEXT Elements Strategy Initiative to form Core Research Center; by the Collaborative Research Project of Laboratory for Materials and Structures; and by the Project of Creation of Life Innovation Materials for Interdisciplinary and International Researcher Development of MEXT, Japan. Mössbauer spectroscopy was carried out by K. Mibu at the Nagoya Institute of Technology, Japan.
Funding Information:
This work was partly supported by the JSPS KAKENHI Grants-in-Aid for Challenging Research (Pioneering) (M.I. 17H06240), Challenging Research (Exploratory) (Sh.Y. 18K19126), and Scientific Research (B) (S.Y. 19H02426); by the MEXT Elements Strategy Initiative to form Core Research Center; by the Collaborative Research Project of Laboratory for Materials and Structures; and by the Project of Creation of Life Innovation Materials for Interdisciplinary and International Researcher Development of MEXT, Japan. M?ssbauer spectroscopy was carried out by K. Mibu at the Nagoya Institute of Technology, Japan.
Publisher Copyright:
© 2020 American Chemical Society.
PY - 2020/4/6
Y1 - 2020/4/6
N2 - ϵ-Fe2O3, a metastable phase of iron oxide, is widely known as a roomerature multiferroic material or as a superhard magnet. Element substitution into ϵ-Fe2O3 has been reported in the literature; however, the substituted ions have a strong site preference depending on their ionic radii and valence. In this study, in order to characterize the crystal structure and magnetic properties of ϵ-Fe2O3 in the Fe2+/Fe3+ coexisting states, Li+ was electrochemically inserted into ϵ-Fe2O3 to reduce Fe3+. The discharge and charge of Li+ into/from ϵ-Fe2O3 revealed that Li+ insertion was successful. X-ray magnetic circular dichroism results indicated that the reduced Fe did not exhibit site preference. Increasing the Li+ content in ϵ-Fe2O3 resulted in decreased saturation magnetization and irregular variation of the coercive field. We present a comprehensive discussion of how magnetic properties are modified with increasing Li+ content using transmission electron microscopy images and considering the Li+ diffusion coefficient. The results suggest that inserting Li+ into crystalline ϵ-Fe2O3 is a useful tool for characterizing crystal structure, lithiation limit, and magnetic properties in the coexistence of Fe2+/Fe3+
AB - ϵ-Fe2O3, a metastable phase of iron oxide, is widely known as a roomerature multiferroic material or as a superhard magnet. Element substitution into ϵ-Fe2O3 has been reported in the literature; however, the substituted ions have a strong site preference depending on their ionic radii and valence. In this study, in order to characterize the crystal structure and magnetic properties of ϵ-Fe2O3 in the Fe2+/Fe3+ coexisting states, Li+ was electrochemically inserted into ϵ-Fe2O3 to reduce Fe3+. The discharge and charge of Li+ into/from ϵ-Fe2O3 revealed that Li+ insertion was successful. X-ray magnetic circular dichroism results indicated that the reduced Fe did not exhibit site preference. Increasing the Li+ content in ϵ-Fe2O3 resulted in decreased saturation magnetization and irregular variation of the coercive field. We present a comprehensive discussion of how magnetic properties are modified with increasing Li+ content using transmission electron microscopy images and considering the Li+ diffusion coefficient. The results suggest that inserting Li+ into crystalline ϵ-Fe2O3 is a useful tool for characterizing crystal structure, lithiation limit, and magnetic properties in the coexistence of Fe2+/Fe3+
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U2 - 10.1021/acs.inorgchem.9b03302
DO - 10.1021/acs.inorgchem.9b03302
M3 - Article
C2 - 32186859
AN - SCOPUS:85082107428
VL - 59
SP - 4357
EP - 4365
JO - Inorganic Chemistry
JF - Inorganic Chemistry
SN - 0020-1669
IS - 7
ER -