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S e p t e m b e r 2 4 - 2 6 , 2 0 1 8 | B u d a p e s t , H u n g a r y
OF EXCELLENCE
IN INTERNATIONAL
MEETINGS
YEARS
Magnetic Materials 2018 Materials Science and Nanotechnology | Volume 2
MAGNETISM AND
MAGNETIC MATERIALS
2nd International Conference on
Masato Watanabe, Mater Sci Nanotechnol 2018, Volume 2
STRUCTURAL AND MAGNETIC PROPERTIES
IN IRON OXIDE EPITAXIAL THIN FILMS
Masato Watanabe
Research Institute for Electromagnetic Materials, Japan
Magnetite Fe3O4 has been known to be a fundamental spinel ferrite
ubiquitously found in nature as a component of iron sand. It also has a
magnetization of 6kG which is high among ferrites, a high Curie temperature
of 858K and the intriguing electronic physical properties of half-metallicity and
large anomalous and planar Hall effect, leading to the possibilities of various
spintronic memory and sensor devices. Sputtered Fe3O4 thin films epitaxially
grown on heatedMgO(100) and other cubic single-crystalline substrates were
evaluated by high-resolution XRD, magnetization measurements using VSM
and SQUID, temperature dependence of resistivity by PPMS, and hyperfine
structures by conversion electron Mössbauer spectroscopy, CEMS. In-plane
and out-of-plane structural characterization revealed that the samples were
composed of a single phase of spinel structure, the cube-on-cube epitaxial
relationship between the Fe3O4 layer and substrate crystals and low FWHM
of rocking curves in a range of several tens to several hundred arcsec.
The magnetization was found to reach 6kG of the reported bulk value. The
Verwey transition around 120K, of which observation is usually difficult in
thin film form, was clearly confirmed from resistivity measurements. The
CEMS showed that the vacancy parameters delta depends on gas pressure
during sputter deposition and strongly influence the structural and magnetic
properties. Epitaxial growth of another attractive ferromagnetic iron oxide of
metastable epsilon-Fe2O3 will be briefly presented.
Masato Watanabe has earned his PhD from Tohoku
University in Japan. He is currently Chief Research
Scientist of Research Institute for Electromagnetic
Materials, a public utility foundation in Sendai Japan.
He has been involved in research subjects mainly on
magnetic functionalities including hard magnetism,
magnetooptical properties and anomalous hall effect
in inorganic sputtered thin films and laser-generated
nanoparticle colloids belonging to the foundation, uni-
versities and private companies.
BIOGRAPHY