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Phase-transformation in iron oxide and formation of Cu/γ-Fe2O3 nanocomposite using radio-frequency sputtering with metal chips on an α-Fe2O3 target

Authors :
Seishi Abe
Masato Watanabe
Source :
AIP Advances, Vol 7, Iss 7, Pp 075317-075317-10 (2017)
Publication Year :
2017
Publisher :
AIP Publishing LLC, 2017.

Abstract

A simple technique that uses radio-frequency sputtering with a functional element on a hematite (α-Fe2O3) target is presented for the production of maghemite (γ-Fe2O3) thin films. These films are prepared on water-cooled glass substrates in an Ar atmosphere. Investigations are done with Ti, Si, Al, Cu, Mo, and Zn, with γ-Fe2O3 being obtained only in the presence of Cu, indicating that phase transition occurs only for this metal. Mössbauer spectra and magnetization analysis reveal that the quality of the obtained γ-Fe2O3 films is higher than that of the film produced using Mg, which was reported in our previous work. High-angle annular dark-field scanning tunneling electron microscopy and electron energy-loss spectroscopy reveal that the added Cu remains in a metallic state (without oxidization), forming a Cu/γ-Fe2O3 phase-mixture in the as-deposited film. The Cu/γ-Fe2O3 composite film exhibits negative magnetoresistance (MR), with a MR ratio of approximately 0.6% at room temperature in an applied field of 10 kOe, and a negative Faraday rotation of −5708 deg cm−1 at 830 nm.

Subjects

Subjects :
Physics
QC1-999

Details

Language :
English
ISSN :
21583226
Volume :
7
Issue :
7
Database :
Directory of Open Access Journals
Journal :
AIP Advances
Publication Type :
Academic Journal
Accession number :
edsdoj.fe0b5dc00410473ba156a34ac7578115
Document Type :
article
Full Text :
https://doi.org/10.1063/1.4996704