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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

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Magnetic Materials 2018

Materials Science and Nanotechnology

|

Volume 2

MAGNETISM AND

MAGNETIC MATERIALS

2

nd

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

M

agnetite Fe

3

O

4

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 Fe

3

O

4

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 Fe

3

O

4

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-Fe

2

O

3

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.

m_watanabe@denjiken.ne.jp

BIOGRAPHY