SPring-8, the large synchrotron radiation facility

Release Date

20 May, 2008

A one-terabyte storage device of a square inch in size will be realized by an ensemble of unit bits in the order of 10 nm.  Because of the small size, unique surface magnetism appears. Its understanding is a key factor for such a high density recording.  Authors have developed a direct method for the atomic level characterization technique for the subsurface magnetic structure.

The spin reorientation transition (SRT) of the magnetic epitaxial film from in-plane to perpendicular direction has aroused continuous high attention.  A Ni ultra thin film on a Cu(001) surface exhibits both SRT and reversal SRT at thickness of 10 and 40 monolayers, respectively.  They are regarded as a basic starting point for magnetism studies in nanoscale.  The magnetism of the outermost atoms can be detected individually by means of magnetic scanning tunneling microscopy, whereas methodology for the case of subsurface atoms did not exist up to now. 

Taking advantage of the Auger electron forward focusing peak as an excellent element- and site-selective probe, authors have obtained atomic-layer-resolved X-ray Absorption Near Edge Structure and X-ray Magnetic Circular Dichroism spectra of Ni ultra thin film on Cu(001) surface.  The surface and subsurface core-level shift is deduced as a function of Ni film thickness.  Magnetic moments are determined for each atomic layer in the region of SRT.

"Atomic layer resolved magnetic and electronic structure analysis of Ni thin film on a Cu(001) surface by diffraction spectroscopy"
Fumihiko Matsui, Tomohiro Matsushita, Yukako Kato, Mie Hashimoto, Kanako Inaji, Fang Zhun Guo, and Hiroshi Daimon
Physical Review Letters Vol. 100 No. 20, published online May 23, 2008.

The details of this article are presented in Japanese.

For more information, please contact Dr. Fumihiko Matsui (NAIST: NARA INSTITUTE of SCIENCE and TECHNOLOGY):
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